I remixed the original extruder back plate from Mide_Welder as it has both screw holes at the same height, but FBG6 original extruder has 2mm in height between them.

Also I made the holes to put brass inserts (2 x M3 5mm length, OD 5mm) and secure it.

Supposedly it should improve extruder work, but I didn't notice any improvement on flow speed. Maybe with TPU it should be working better, as reducting retraction lengths.