Yeah, if you're going to use Clay you definitely need to go all out. For a build like that I had in mind filler cards like Acro Bike, Judge Whistle, Lusamines to recover discarded Stadiums and Supporters, Pal Pads to recover energies, and like I said, go all out on pokemon and energy recovery. Hell, you could use Rayquaza GX to drop even more cards on your turn and use its GX attack since your deck wouldn't rely on GX attackers. 120 + 170 = 290 (Drill Bazooka hit after getting behind on Prizes with dojo active) means you 2HKO both Reshizard and ReshiZekrom, and you already OHKO everything on Dark Box and PikaZekrom with the option of Crushing Hammer to get rid of Weakness Guard Energy.
The deck biggest problems would be Giratina variants since the guy only gets OHKO'd by Eleventh Hour Tackle and Drill Bazooka + Dojo when behind on prizes, something that can't be surmounted as easily when going against SPA decks, and MewMew in the variants that are otherwise weak against you (although you can slow it down with Power Plant).