Yeah, I don't like those wing nut molds AT ALL. I can hardly imagine a less handy way of cinching your mold up.
Plus, they don't have a rounded end for a cap.
Pluplus, they don't have a flange or whatchamacallit where the one side of the mold fits into the other.
Ideally, I hope for a mold with a cam latch like my fecto mold, a rounded end on each slot, and those mold flanges.
At the very least, since I've never seen another with a handy cam latch, I'd settle for the round ends and flanges; then use a C clamp, or score some of those clamping latches from McMaster Carr.
some day....