There isn't a huge amount of horizontal passage in the entrance series. Just the meanders, which are pretty easy. I carried two bags through at one go last year on a rigging trip and it was fine. They weren't huge bags. Probably about the size you mention. More of a slog once you get to the bottom of Aldo's and the Starless River - easy caving as far as Camp 1, but quite a long way. You don't want more than one bag each below Camp 1 if you can avoid it, especially in the Couffinades and the Canyons (the hardest part of the trip).