To add to what Timo says, we too, have seen pretty shoddy seat grinds coming out of most aftermarket head suppliers. There's nearly ALWAYS improvements to be made.
We also advise our customers, if supplying heads for us to build, buy them "bare". The hardware various aftermarket companies use, including Edelbrock, "meet" minimum requirements. They don't "exceed" them, and in a performance build, EVERYTHING shoulld exceed requirements for durability.