(*If you have an active spirit sword and don't hit anything, then decrease your max mana and trigger spirit sword again, it won't override the previous effect just refill your mana. You can refill your mana this way countless times as long as you don't hit anything, don't increase you max mana or lvl anymore. If you break the combo, it will only work again if you do the entire process, including the max mana decrease.)
This is both a tutorial on how to make infimuters on your own and a collection of my discovered methods.
I may edit it later for people who are uninterested in the 'science behind it' and only want to try it out.
The classic method is boosting health and/or mana ridiulously at lvl 1 on a potion race and chugging those potions between B2P - Fire Heart shenanigans. This is inefficient and scum-heawy.
By adding the spirit sword trick which refills your mana completely, we can cut down on the stat requirements greatly and create methods that work past lvl 1... even methods for lvl 10 exist.
It's worth mentioning that the original halfling method was max mana independent, but by adding spitit sw. it becomes a mixed method where max mana is a meaningful stat too. Most of the strats are mixed, except for gnomes who can become health independent (and due to this lvl independent too) at certain max mana thresholds.
So how do we create an infinimuter?
We want to have enough max health/mana, that by using B2P some other glyphs and Burndayraz we can cast so many spells that we break the CP threshold, and with the bug we refill our mana. This is 1 cycle. We also have to find a way to make sure that the health change between cycles isn't negative.
So first we always choose our glyphs, items for raising stats (if necessary), healing and additional mana generating method. Then we write an equation system with 3 equations: 1 for mana change, 1 for health change and 1 that accounts for all glyph casts and is equal to the CP threshold.
It has some degrees of freedom, so it can't be solved just like that. But you can pick the values of some variables like either max mana/health some glyph casts or debuff counts if you have the Naga Cauldron etc. then everything falls into place.
You shouldn't predefine both max mana and max health at the same time, cause it can lead to impossible stuff: like cast B2P -13.5 times

Doing all these calculations would be time consuming/boring especially if you did it multiple times to find optimal solutions, so let's do all these in excel instead. I'll give an example:
1. Let's make a halfling infinimuter who casts 1 BD on the target every cycle, makes mana by B2P and spirit sw, spams Lemmisi for CP and heals by Naga Cauldron boosted health potions and the 5% Fire Heart charge.
For any given max mana this is what we need:

What I did was that I wrote all the variables in columns grouped together, and made 2 extra in the end (health/mana generation to check whether possible).
I preset the mana, BD cast, debuff count, made a function so Lemmisi count with the other spells adds up to 27. I wrote functions for h/m generation too, with EVERY relevant variable included.
First I adjusted B2P count till mana gen became 0. You don't want it to be positive either because that costs extra health.
Second I started adjusting health. It had no effect on mana gen, since that only depends on glyph casts. Any health value is good that makes health gen at least 0. I wrote the lowest possible values there.
After these I copy pasted it with the functions kept, and searched for solutions with different mana/health values. When I changed something the health/mana gen columns showed the result.
Things to notice:
- req. health depends on B2P count
- more max mana means bigger refills, less B2P dependency, less health need
- increasing max mana is only meaningful by 3 points: it let's you convert a B2P into a LEM,
any less is wasted
I also checked what happens if we play around with debuff counts, and tried a different glyph setup too. Halpme is an escpecially great glyph to use; it heals directly and indirectly by FH.
It's also easy to convert working B2P-LM-BD methods to fit in Halpme:
Trade 2 Lemmisi into 1 B2P and 1 HM: same mana cost, CP, but heals 1HP/lvl and 5%.
This table shows how much improvement does having HM provide:

Not carrying Naga Cauldron is viable too. In some cases you will see LEM = 0. In those, you don't need Lemmisi anymore, so you have more inventory space to use. Helps when you prep JJ or want to carry an extra RBS.
This table is about the gnome infinimuter variant, with same items:

Mostly undoable without HM, on the other hand gnomes make up for it by being able to work at higher levels too. With halflings nothing works past lvl 3-4, for gnomes even lvl 1000000 would be a piece of cake if such thing existed.
Generally gnomes start disadvantaged but catch up exponentially with each max mana increase.
I colored some methods in green (easiest ones), yellow (work at any lvl with any hp), gray (impossible due to inventory space limit - so I didn't bother finishing the calculations either).
Here I showcase some gnome methods designed for lvl 10:

Labels are missing, but the same as everywhere else. Don't mind the 10s, they were a variable for level.
Where the mana gen is negative, it just means you need Mystic Balance or that much extra mana.
So far I only showed setups, and how many glyph casts are required here and there, but did not give any tips about the casting order, but that's important too!
You have a lot of freedom when you create the order as long as you waste nothing - or have excess health and you're allowed to waste some of that (but not mana).
Useful tips:
- start the cycle with Burndayraz, continue with B2P or LM
- use spells in great masses, so there are less steps and are easier to follow
like cast B2P until your health runs out/mana fills up continue with HM untill any more would waste health...
- add FH/potion drinking at a point where the mana/health count or CP is unique and easy to remember
- finish cycle with a spell that costs mana and is not B2P - no mana is lost
(though you couldn't even do this without excess mana)
For most races not every cycle is exactly long cuz their CP threshold is not a multiple of 3.
Like halflings have 2 long 27 spell cycles followed by a short 26 spell cycle. In the short cycle you need to cast 1 less spell which can be a Lem, or a HM but has to be compensated by more starting health or a counter HM in the next short cycle (you trade BD into it).
Gnomes have no such problems.
Before I continue this topic, I'd like to hear if you're interested in the continuation, also any criticism/suggestion is very welcome!