Centre of balance point is 75mm above the bumper centre-line. It's very easy to work out.
The F&R bumper mounts are plenty strong enough to support a bare Z shell.
FWIW we have two rotisseries that we made from engines stands with the centre mast raised by 400mm.
Don't over think it - they are easy to build.
Hi all, I figured i would post some pictures of wiring diagrams here, these are later Australian delivered 260z 2+2 wiring diagram, they suit mid 76 to 78.