Dreamdancer wrote:LEMMISI and BLUDTOPOWA wouldn't really work, since both need tiles. In both cases you lose 3 tiles and get 3 conversion points.
Nope - you can cast both of them freely even when you've fully explored the current floor. Hence why I said to look for a fully revealed subdungeon (or just fully explore the subdungeon first).
LEMMISI will consume 2 MP and give you 3 conversion points. 0 tiles consumed.
BLUDTOPOWA will restore 1 MP, take away 3 HP, and give you 3 conversion points. 0 tiles consumed.
After casting BLUDTOPOWA twice, you can cast LEMMISI again.
Keep doing that until your HP and MP are too low to continue. Then go to the surface, explore, and return.
Every 12 tiles you explore will give you 12 HP and 12 MP. (Going with 12 tiles to avoid decimals in the following calculations.) When you return to the subdungeon, you can then use that 12 HP/MP to cast LEMMISI 6 times, BLUDTOPOWA 4 times, and LEMMISI another 2 times, thanks to 4 MP regen from BLUDTOPOWA. That's a total of 12 spells cast, at 3 conversion points each, for 12 tiles. Far more efficient than any other method.
Remember, I also suggested getting the Bloody Sigil. That doubles your HP regen at level 1, giving you 24 HP for 12 tiles. You can now cast BLUDTOPOWA another 4 times, and LEMMISI another 2 times, all from those same 12 tiles, for a total of 18 spells cast for 12 tiles. That's 1.5 spells for every 1 tile - in other words, you're basically casting a 0.75 MP spell and getting the full 3 conversion points for it. Multiply that by, say, 200 tiles and you have 300 spells cast or 900 CP. Not bad for a gimmick strategy!
(This isn't taking Spirit Sword into account, obviously, which may reduce the efficiency of your CP harvesting - although you can try to time it so that it doesn't hit until you're out of MP anyway. You will, of course, end up with a ridiculous temporary attack boost.)
Edited because my math was wrong.