I've always used 1 piece on my 77s but the Tasco Custom Shop is 30mm so I used 2 piece. Up to now it's not budged at all and I can have the 2 piece as far apart as I wish.
Have you never had a Bullpup springer Holly?
I know Keith made Pups out of the 77s and TX's.
I'd rather fancied getting a 52 sidelever and tuning it and putting it in a Ginb bullpup stock but they've stopped production now.