I use another mold to hold hooks up. Works great as it is at the same exact height. Oil the mold hinge so it closes with less resistance. This helps too.
This is what I do, and I have used wood that I had planed to the appropriate thickness. If there's any "trick" it's to not move the mold until it's completely shut.
When I have a problem with hooks moving, it's usually with a spinnerbait ort buzzbait mold. With jig hooks they tend to stay in place, unless they extend past the edge of the mold enough that there's more weight off the mold than is on. Even though wire forms are attached with the other molds, the hook weighs more and those I have problems with unless I use another mold or wood to prop them up.
I also have some molds, that I have bought used, that had rare earth magnets installed into the mold for holding hooks. I've seen that mod for the ned rig hooks and that uses a magnet strip. My molds have round, cylinder shaped magnets, where they drilled a hole & pressed the magnet into place. I don't think any of the molds are Do It, they're all customs that had been made for someone else, but the same can be done with Do it molds.