I'd say bad idea.
If you really want to know what it would taste like, do this experiment: put a couple of drops of
e-liquid in your mouth, swish it around and see what you think. Doesn't matter whether it's 0 nic or not.
The reason I say this is because no matter what you do, it's not going to dry out completely.
It's the nature of e-liquids.
It's not just water and flavoring in there.
Both VG and PG are humectants: that means that they absorb water - not just carry it.
So what you would end up with is a gooey tab of Stonewall that tasted like e-liquid.
You could try just plain flavorings, but I think you're going to be disappointed no matter what.
Edit:
And remember: the idea of Stonewall is to slowly dissolve while your gums and mouth have a chance to absorb the nicotine. Making it taste better would probably just tempt you into sucking it harder, and not giving it a chance to absorb properly.