Understanding valve seals

Although this does not necessarily address your oil consumption issue, I cannot believe anyone else hasn't said anything about it.

Just to get it right in my mind, you said you used different length pushrods in your engine because the valve stems were all at different heights, is that correct? That has to be one of the most difficult and expensive band aids I've ever heard of in my life.

You should have sent those heads back to the shop that did them and had them redo those head and get them right.

Lastly, to your "oil consumption" issue. You're trying to chase oil consumption at 500 miles? For real? If this engine were under a factory manufacturer's warranty, they'd laugh at you and tell you to put enough miles on it to break it in, because IT'S NOT. ....and you're tearing into it to fix a problem it may well not have.