I added some of the Pearl X bright gold pigment to my Leading Lady, going for something that looks like OPI's Senorita Rosarita. I put it on this morning and like it - the gold adds just a subtle shimmer - I may add a little more to make it a bit more noticeable next time.
Since I have It's a Lily in Gelish, which is very similar, I didn't mind making a franken out of the whole bottle of Leading Lady. I just added the pigment straight to the bottle after mixing a little on some foil and curing it to see if it would work.
I'll try for a picture later tonight or tomorrow.
Anyhow, no problems with shrinkback or anything. For me, it works just like Gelish and ACG.