The Taigen 360 deg adaptor kits come in a variety of flavours (depending upon model and firing system). However, some of the slip ring wring harnesses for these kits incorporate a second MG led for the turret. As far as I can tell, this would allow you to have the bow MG, as well as a turret MG, connected to a standard Taigen/Torro MFU. I've not tried it personally, but in theory it should work.
Forgebear will probably have the adaptor kits.
