Nice work. I have compared quite a few 2 3/4 hulls and their volumes. Alot of my learning has come from trying to fit given loads in them. The largest volume hull I have come across is the old maroon Federal unibody hull. It was most common in 1 1/4oz steel shot loads. My MEC Sizemaster does the trick for sizing those tall base hulls and it isnt a problem. The Cheddite hull is next in volume followed closely by the old Activ hulls. Since both the Fed unibody and the Activs are hard to come by, I sort of drop them from being a useable source for hulls. BPI does offer a new clear plastic hull that is the equal to the old maroon Fed unibody. But starting with new bought hulls can be expensive when free hulls can be had at your local range.
The paper basewad hulls do offer a lower pressure but always have a reduced volume. I am not a fan of the fast 7/8oz or 1oz loads unless all of my shots are over decoys. I never get those conditions so its not in the picture for me hunting public spots.
I have found quite a few hulls that have slightly less volume than the ched hulls and work well for a sub. To sub them, I only have to reduce the pellet count four or five pellets. These are the orange Nobel Sport, purple Fiocchi, Diana, Keman, dark blue Rio and Mirage. The Mirage hulls, come in various colors and you have to watch the base wads in these as they tend to vary in two heights. Rios come in varous versions, only the dark blue trap hulls seem to have the higher volume needed.
Also the Fed GM hull has slightly less volume than the ched hull but unless you find them at the range, they are pricey to buy once fired.
Cheddite hulls can be found in the following,,,,,American Target, Challenger, Centurion, Kent Fasteel, Kent Trap, Tru-Tracer, Gamebore, Herters and Estate with brass base. New Ched hulls are readily available new from both BPI and PR.
If you are trying to load 1 1/8oz loads, I think the ched hull is the way to go. Its an excellent hull and not hard to come by if you know what to look for. There are no doubt other variations of the ched hull, I just havent run across them yet.