Ebay GT45 + 5.9 Magnum + E85 blow thru

Low 12s isnt really that lean for E85 at that low of boost. I tune 600whp 4cyl around 11.8-12.1 on E85 all day.

I haven't messed with FiTech but 50% trim seems REALLY high. Are you sure you're not hitting a trim cap?
Regardless, the high trim % is screaming at you to "FIX THE MAP!" The 5000-6000rpm range above 130kpa to 150kpa needs more fuel.