your statement is generally correct, however, since the valves rotate, i use the "apply very light pressure, while twisting the valve with your thumb" process to see what the contact looks like. then, if not the whole way around the seat or valve, apply a little amount of compound to get a perfect pattern [one i'm satisfied with], then as a final test fill the chamber with solvent for a leak test. i do very few heads, and only have very old equipment at my disposal. this works for me, it appears your method is the "correct" way, and should be the followed practice if one does way more work in this area than i do. no disrespect intended toward you [or others] in any way. please accept my apologies if offended.