What type of bag for the rear?

[Low68]

I am thinking about putting bags on my truck, and am trying to figure out which bag to use for the rear. We put bags on the back of my dad's 01 full size and when we bought the kit, it came with the standard convoluted(I think?...they have the two squashed balloon shape) bags. Then we decided to buy the airride kit for the rear and it came with the sleave type.

My question is which bag do I need for the back of my truck? If I use a convoluted, do I need the 2500 lb or the 2600 lb? Thanks for your help!
Low68