I have an alloy rear tub on my build Skov
Going to replace the book spec mounts with a twin bolt set up as you described.
I did move the rear back stays a little more outwards, once bolted up, I intend to bring a stay from the underside of the back stay mount to the top of the outer edges of the diff mounting cage ( I hope that makes some sense mate )
Here is the best picture that I can find at the moment, not very clear but you might be able to work out what I mean !!
Excuse the cheesy grin, I was feeling rather pleased with myself after finally getting the chassis rolling
This is an old photo, I will be replacing the cross bar with something a bit more HD & will probably do the same with the back stays
