Summary My copy of BigBox Hybrid Dual Fan Alternative by GregoryHolloway printed in black Edge filament was wilting in the heat between the two hot end blocks. I decided to try and modify the blower ducts to provide a shorter, straighter path to both nozzles. I'm still testing it out but it seems to work well so far. Still uses the standard BigBox Hybrid mountings and 40x40x20 Blower Fan.