If the blanks are bought, then they will all be the same size, so some kind of former would work. I intend to make my blanks with a duplicator, so in a few months I will be in the same dilemma as you.
My plan is to make some molded cradles, using a mix of polyester filler and resin to make it pour able. It is very cheap and sets up hard and quick.
My plan is to make a wooden mold box only slightly larger than the body. I will take great care to cut a lip slot in the lure body, this may take a few attempts to get it perfect. I will then fit a balsa lip, square, so that it touches the side of the mold box.
Wax up the box and body, pour the resin mix and push the lipped body, nose first into the resin, so that the lip is square to the box and the bottom edge of the lip touching the side. Taking care not to push the body too far in, or it will be locked and very difficult to remove.
On a belt sander, remove material from the bottom lip side, until the balsa is visible.
Offer it up to a squared band saw, if the angle of the lip is slightly off, the cast block can be adjusted on a belt sander, until square. This operation will be made easier if four feet are molded into the casting, by drilling 4 x