Those that do use the snail capper on the remmie nma do end up cutting the slots larger. I have see 2 techniques actually in other threads on this forum. One folks use a dremel of some such and end up with a semi circular bottom in the slot. Others with access to a milling machine or really good hands with a file make square notches just like a colt.
Think my solution to the problem will be 4 in line cappers, already have 3. That will give me about 80 caps. Just counted, have three different kinds one goes back to about 1983 when I first made a black powder rifle from a CVA kit. It probably holds 23 or 4 caps as it is somewhat longer than my middle sized that holds 20, have a shorter one that holds about 17 is should think.
If I really needed a lot of caps during a match, I could always shoot the 1860 armys, or mix and match.