I just sold my 24 gauge and reloading equipment last week. Here's how I loaded for it after purchasing the 24 gauge roll crimp head directly from GAEP. I also purchased a 28 gauge MEC Supersizer, opened the collet to size the 24 gauge head and mounted it on a plywood base that I C-clamped to my drill press table.
Step 1. I used a 20 gauge MEC Sizemaster to deprime, reprime, drop powder, insert wad and drop shot. I then placed the hull in a loading block that was either a 12 or 20 gauge MTM 50 shot block for their large cartridge carrier box. I also bought a 15mm arch punch to punch the overshot wad from thin cardboard like cereal or shot shell boxes or beer coasters.
Step 2. I aligned the Supersizer with the roll crimp head and used it as the vise to hold the hull for roll crimping. This sized the head at the same time.
It's slow but it works.
