you are on the right track for testing for leakage but dont get too worried about a small weap as as soon as you start the engine it will start bedding the valves even more flatttening all the micro scopic high points and sealing completely .
if you have aleaky valve the best way to see where it is is too use bearing blue or engineers blue . and put a fine coat on the valve and slide it onto the guide and slap it down onto the seat ,
dont turn the valve and then pullit out and check for sealing .
it will show up any points of leakage. i have used this for years on 5 valve motorcycle heads and it works.
hope this helps.
