This deck needs a big hand refresh as often as possible, so you can draw upon the supporter you need at the time. You should run at least (3) COPYCAT. Your opponent will be loaded with cards, and you will draw from 8 - 12 cards every time you drop it. I crushed a Sablelock deck at league last week from a guy who top cutted Nationals, and I drew about 13 cards with a Copycat. Had everything I could possibly need on that draw including full Gengar line, BTS, etc.
You should run the new FLOWER SHOP GIRL card instead of Palmers. As you will be losing basic/stage 1/stage 2 in your Gengar line, plus 2-3 energies, the card is perfect. I run (2) of those.
Pokemon collector (3) should be fine; Bebes (2-3), PONT (2). I also like Cynthia's Guidance. You almost always pull a very useful card when looking at top 7 of your deck. Also have a couple Interviewer's Questions -- to pull needed energies.
I teched a Staraptor FB (X), as it's power lets me choose any supporter from my deck each turn, and no biggie if it gets sprayed. I think I'm going to change this out for a 1/1 Blaziken FB line -- for the added Dialga G tech. Got to have a good one of those. Any good Dialga G player will SPRAY your "level down" PokePower as soon as they see what you're playing -- for sure. They'll let you drop an Uxie and set up a bit -- then save a spray for your Gengar X.
LuxChomp players are going to bright look the Vileplume, then 1-shot it with Uxie X and 1 DCE attached. That's what I would do.
Anyway, hope this helps. Our deck is doing very and is really messing with the SP players -- nice!