727 sometimes not going in reverse

That is correct, Ma calls the Hi-drum "front clutch", and she calls the Forward clutch "rear clutch". I may have forgotten to mention that.

And OOPS you are also correct that the TFs do NOT have a VB to case gasket.Sorry to be so confused, ignore all references to the gasket, and instead, substitute, machined surfaces or something to that effect.

As to the 2Turns spec, I have never really,( after the first couple of trannys) paid much attention to it. I set all bands by a 1/4 inch rule, That is to say, there should be about,(oh boy), 1/4 inch clearance under the apply arm to the pin.I've never had a complaint as to band action.When I was rebuilding these back in the day, there was no way of knowing what these finished units were ever going to end up in.Since there were several different specs for various car lines and engines and years and even band types; the 1/4 inch rule was established, for every one.Just saying.The big thing is to ensure that the band retracts off the drum while still staying in the working range of the servo when fully applied, and still have some room left to ensure you won't have to drop the pan every couple of months to reset the band due to wear..Sheesh; that right there, is a pretty long run-on sentence.
Love your shifter!