me and steevo are having a little competition lol. Its too see who can get the most mana on the steal mana secret gem level. the current record is 4.006.444 mana. Set by me
Well, I haven't figured out exactly how, but I think that it has something to do with the number of gems, not the grade, also I think it has to do with when you add the towers.
when you're going for max mana there's no use in trying to kill a creen early on. that only gets you a higher score.
use low level gems early on to make sure you get as many hits in on a creep before you kill it. but then higher level gems have higher multipliers and building towers get expensive after a while. so its all about finding the sweetspot where you get many hits, and still kill'em before they reach the end.
in my last setup you can see that lower level gems are places in the start of the path just to get some hits in and draw mana. the higher level ones are at the end to finish them off and get even more mana.
i had a thought early on where i was gonna let creeps run more rounds. thought maybe you get more mana in one round than it takes to banish. that way they go round and round , getting even more mana with low levels gems, but it seems to be balanced out. couldnt find the butterzone anyways.