Kuch: you might have 80# and 76# Bear TD limbs, but not for the 76er as I assume you know. If you take off the pocket clips, grind the riser ends flat and bolt on new limbs, you can safely shoot 60# using these risers. Personally, I wouldn't trust custom made slide-in limbs over 55#. I've seen risers with broken clips that probably broke with the stock 45 or 50 pound limbs.
I agree with you regarding the 76er, with stock glass limbs, being an underrated bow. These bows can be made whisper quiet and are accurate. I have the Custom and the Deluxe. I bought one when they first came out in 1973. Some folks mistakenly believe they were introduced in 1976. They are not a fast bow but are no dogs either. Back in 1976, I preferred my 76er over my brother's 1976 Grizzly. The Grizzly was just a bit faster but not as smooth.
Joe