Revo Hybrid diff V3

Do the Hyper ST ring gear have exactly the same profile as the Caster Racing ring gear or just similar? Has anyone tried this?

What other diffs will fit the V3 diff cases?
Mugen MBX6? AE RC8? Ofna Hyper 7.5? (UE diffs are 7.5 diffs, right?)

I am drawing up some custom diff cups for the caster racing differential that I will machine for myself if no other fix comes up. Aluminum diff cup with titanium inserts.. Being a machinist has its advantages sometimes!