It might seem silly to mention this (it may be obvious), but Expert Belt holds added bonuses for Rhyperior. It increases the potential damage of Raging Drill by 40, and increases the chances of KOing something with Deep Scrap for the mill.
I personally don't use Delcatty in my Rhyperior; it seems too much like Dragon Rush bait. Instead I run 3 PT Dialgas, and nearly half my deck is energy. That way I only use the power when it's absolutely necessary; attacking with Hard Crush generally knocks things out without stacking the deck. Because of the high energy count, I run Spiritomb as my set-up Pokemon, although Sableye could work too. I find Spiritomb to be a little bit more consistent and helpful for the way I play the deck, especially running 4 Call Energy, but I think it's more of a personal decision than anything that has a clear advantage. I also run a 2-2-2-2 Rhyperior line. Very minimal, just because I use so much space for energy.
These are things that I've done; maybe you'll have more success with a traditional build. In any case, I wish you luck. Rhyperior is a really fun deck.
