You dont need much hull sticking up to get a good roll crimp. I used to roll crimp my 2-1/2 hulls when they were getting too worn out for fold crimping. I woild cut them down another 1/8 (so to 2-1/8) and then roll them with the same load. Then toss them after firing them.
I have not ised lubricant before. I had good lick with bringing the crimper down to the plastic and allowing just a second of spinning on it to warm it up and then plunge down the crimp. Has always worked well.
Having to much material to have to fold over can cause all sorts of issues which i think may be your primary issue.
