Valve to piston clearance?

OK just asking, but
302 heads are the fast-burns right?
If that's right, then you are so close to having a tight-Q situation, all you need to do is get the pistons a little closer to the top of the bores and run the .028 gasket.
IIRC the KB 167s will get you close to -.012. That plus the .028s will get you .040 about as good as it gets.
With the tight-Q comes a more efficient design,. Usually followed by a snappier engine and a little more low-rpm torque. This is usually followed by more mpgs, because you cn run a little less gear and not so much TC..
Now your Q-situation totals .030 plus .039=.069; Which with closed-chamber heads, I have read/heard , is possibly inviting detonation.
If it was my project, I concentrate on the either more Q or less but , I have heard that the troublesome zone is .050 to .080, and at .069 you would be right in the middle of it.