Yes I have. Even with iron heads, I had a very slight seepage at rear of driver side. A dab of silicone there always took care of it. These covers are not military grade machined so this cover was prone to seep.

I did dump a bunch of flour on a sheet of glass, sat each valve cover on it. There was contact all around each cover,,,,by examining imprint in flour...however the imprint was a bit less defined at rear of one of them.

However a gasket should take this up,,,,and in fact my gaskets are again imprinted very well when examined upon removal of valve cover,,,,,just very narrow at leak points.

But as I look at crush imprint it should be sufficient,,,,but where head platform is narrow,,,it almost looks like it was dremel tool ground down where it is so narrow,,,looks like tooling marks here,,,almost as if machining a bit more clearances for base of valve spring. Which by the way triggers a thought. I had a machine shop setup heads and also install ‘beehive’. Wonder if they may have done a bit of clearance fine tuning. Each rear spring is pretty close to pocket at edge of head.