I think you'll find Sloppys will be ok. They are 1/48th scale, which in theory is 36mm, & Mark's figures are 30/32mm.
I think any vehicle 1/48th or 1/43rd will do. Keep an eye on Mark's Instagram, I'm sure he'll feature more vehicles there.
Mark will be sharing his home grown rules at some point, but in the meantime try Contemptible Little Armies by Mark's chum Chris Peers.