Is overspray on cylinder head ok?

Best thing to do is instead of taking pot shots at length, is use a checking push rod.
Call Smith Brother's and have a set made took a week to week and a half. Well worth the wait.
^^^ THAT ^^^

Don't forget there is a difference between the ball-cup length and the overall length.

I ended up with a 7.080 ball-cup length on a 360, e-heads, hydraulic cam, and 273 rockers.

I used oepushrods, had to call and do things the old fashioned way, but had my parts in under a week.