I thought I'd share some of my experiences with Flay 'Em with you. First off, adding a purify, even unupped, is a great idea. A third, maybe even half the wins turn into EMs and the extra cash is always welcome. Secondly, use a skip guide, the FG Efficiency Study recommends skipping 15/29 gods. Thirdly, decide carefully what to fractal and when. And fourthly, know what to target with your pulvy.
Here is a last turn win against Osiris. Against this FG getting one or both mind flayers out in time can shut him down completely, but once he starts spamming scarabs there's little you can do, unquinted creatures will be eaten immediately. My gamble to quint one mind flayer - both golems or rather destroyers were deep in my deck anyway - didn't work (with turtle shield while you haven't played a pulvy yet that's bound to happen), the one golem/destroyer couldn't be grown large enough in time. And my other destroyer was my last card but I knew I'd win because I could play and fractal him him and had enough fire quanta to bring out five more and kill Osiris in one turn.
Also a last turn victory against Miracle. Miracle can be next to impossible because he has so many of his name-giving cards and so much light that he gathers the necessary 12 light quanta easily. So focus your pulverizer on those light towers, even if he still has ten of them with ten turns to go. In this case, he last miracled with three light towers (plus his light mark x3), so he had 6 light quanta with two turns to go, I destroyed one more tower and thus on his next turn he only had 11 light quanta and couldn't play a miracle, allowing me to win on the last turn.
And just one more tip, Lionheart. This might go for all decks that simply chain dim shields. The more quints, Anubises and hourglasses he has, the better. You can remain totally passive, never play a creature or your weapon and just wait for him to deck out. Once he's quinted his whole board he cannot rewind creatures nor eat them with his scarabs and he'll usually keep on drawing cards until it's too late.