I tried my luck using efishs high zuit core shot method and here's what I came up with.

Flippin zip

Thump Grub

3.5" Swim Shad

It went easier than I thought it would. Of the three baits the Flippin Zip turned out the best and pretty much how a guy would want a core shot to turn out like. Though it's a little tedious getting the trimmed body back into the mold. Hint - A little worm oil helps with that a LOT. I'm real happy with how those turned out.
Knowing I was probably going to have issues with the Thump Grub I only shot one of those. Making a pin for that bait was a little tricky. I ended up cutting the pin to length then ground one end down to a fine point so it would allow the plastic to fill the mold on the initial shot. That part worked like a champ as far as creating a core space. Since my pin was so tapered ( about 3/4 of an inch and needle sharp) I had to trim the the first long section of the bait off so the core plastic had a large enough opening to flow through. That left me with the head of the bait being the core color plus there was a little blow by as the core color covered a little bit of the main body color. I'm OK with that as I usually cut an inch off the bait when I fish it anyways. If you are looking for a full size Thump Grub that doesn't have a head the same as the core color then the tapered pin probably won't cut it for you.
The Swim Shad too suffered from a little blow by. Though you probably wouldn't know by this picture, the bait on the left is turned out great. The two baits on the right both had blow by issues. Re: Blow by. It's not a deal breaker by any means. The fish won't give a rip one way or another but if you are looking for perfect results every time then blow by may be an issue.
All the pins I made were made of 1/8" brass rod. For the Flippin Zip, I just cut them to the length I wanted and ground the ends to a rounded end on the bench grinder. They lay right in place no problem - Easy !
The Thump Grub I needed to grind one end as thin as I could to as fine a point as I could. That ended up being about a 3/4" taper. The other end I just rounded off.
The Swim Shad I just ground flat at each end of the pin. That allowed the mold to close completely. It also kept the pins in place , sort of ( LOL ) and allowed enough room for the plastic to flow.
Many thanks to Efish for the great idea.
Oh, and I killed my first Mosquito of 2017 in my garage today. 2XL 1 - Mosquito Nation 0