Ok, I just managed silver finaly (many tries) with early wonnafyt and early mysterea into mystic balance, the small mana pendant, the -10% orb to take that much health off, and then pretty much straight fireballs (with one lucky dodge at some point, but otherwise had a bit more than enough). Two hits of magic, and I picked up flames at some point during the boss fight (earlier than it was wise, but turned out good). Nasty level, very intelligent way of making the tinker fight without his regular shennanigans.
Way too scummy, unless, as Avatar said, we've been missing something obvious. Wouldn't mind seeing it made a bit easier, as it really is harder than most golds.
Now to see what gold looks like after such a silver.
EDIT: Gold looks awesome though.