I used to be big into making a variety of colors. Core shots, split veins, hi-lites........you name it. Then one day I got to thinking why??
I have fished our local river for about 40 years now and there are still 2 colors that dominate over all soft plastics in that water: Watermelon - red flake for main river, clearer water and Green Pumpkin - red flake for ponds and more stained water. I might throw an oxblood color or red shad from time to time, but those colors are about as solid as it gets for me.
Now if I make a watermelon - black flake worm with a red core shot vein, am I going to catch more fish than just adding red flake? I doubt it, but one thing I DO know is the bait will be much harder to make.
If you are one to experiment (like I was once upon a time) and just wanna have fun with it, by all means do it. But I would ask myself these questions......
Are core shots nicer looking? Yes
Will they catch more fishermMEN? Maybe
Are they harder to make? Of course!
Will they catch more fish? Possibly, but is it really worth the extra effort?
If you decide to make core shots, I think SlowFISH nailed it with a light smoke outer color, touch of hi-lite and a vibrant core. Red, green, blue, or purple. Another combo I'd like to see is maybe something that resembles a sexy shad pattern as I've been catching fish on wake baits in that color. Maybe a blue smoke with a yellow vein. Perhaps some white flake (if they even make it) or something similar?
Whatever the case, I hope you have fun doing it and wish you the best of luck!