Every set of stage 6's I've done have had some sort of issue that I hadn't seen with them before, and even though as a whole these weren't all that bad(in the grand scheme of things in the stage 6 world), they didn't disappoint in that regard.
I thought I had a good before/after pic of this, but I apparently didn't take an "after" pic.

I'm not sure why these ended up this way, and it's not really that big of a deal...... But something I hadn't run into before.

The massively deep spring pockets, which get modified for better drainage so the tops of the seals aren't submerged in oil, aren't a "normal" size.
They're too big to properly locate a 1.550 type spring if you only wanted to run a shim under the spring, but they aren't big enough to fit a spring cup.
And the guides don't stick out of the top enough to run a spring seat and still get full engagement of the seals.
So, they need to be opened up to use a normal spring cup.

On this set of heads, the spring pockets were no where near centered on the guides.
On some of the holes, it was cutting about .060 out of one side, and not even touching the other side.

The one before pic I have, you can see how one side of the spring pocket wall is much thicker than the other.
After recutting, they were much closer in thickness all the way around.