For the Heritage ad panels I use UltraPro 3 pocket pages which the box says are good for 7 7/8" x 3 5/8" and they work very well for mine.
For the '86 Donruss pop-ups I use UltraPro 6 pocket pages which fit up to 2 1/2" x 5 1/4" and they fit perfectly in those.
I'm sure BCW makes a comparable product. I bought a bunch of boxes from the UltraPro site when they were having a sale + free shipping deal so I got a try out a lot of the pages first hand haha.
Seven Costanza
Assistant to the Traveling Secretary