In general for CPC, you'll need larger racks. Justin racks, Paulson, and ChipCo are all too tight. I used cheap Chinese 68mm racks for my CPCs that fit the best. For most CPC molds, there is a fair amount of height variation which means some barrels will fit a smaller rack and others will not. But the 68mm racks seem to fit most or all barrels fine.
I know
@T_Chan stocks some of these. I can't remember where I got mine originally, but they are out there.