My Jobo CPP-2 came with a 2830-2560 combined tank. I am not sure how the original owner used it, but it allows two 7x17s to be processed at a time. The interior is 20 7/8 inches deep. There are ridges of two different heights running lengthwise. The four higher ridges allow two 7x17s to wedge in place on either side off one ridge. The other 7 inch film edge wedges against two more ridges leaving a gap of 1 7/8 inches. The fourth ridge runs down the middle of this gap.

A sheet of film 8 inches wide could wedge between these two ridges placed on opposite sides of the tank interior. I have not tried this tank with 8x20 film, but it appears to have that possibility.

Sorry Steve. This has come a long way from backpacks.

John