When I reloaded I cut straight wall 16 gauge hulls down from 2 3/4" to 2 1/2 inch and reloaded them on my Sizemaster using the standard MEC plastic die. I got acceptable crimps.
Keep in mind that you'll probably get only 2 to 3 loads from the roll crimped hulls before they are toast. When I roll crimped my 24 gauge hulls 3 reloads was about the most I could get and that 3d load was a pain in the ass to insert the wad because the hull mouth was so messed up.
I would only roll crimp if there was no alternative such as 24 or 32 gauge which have no practical reloaders or 2" 12 gauge where you need all the space in the hull you can get.
