If you've gone to all the trouble to remove the head, get everything done. You would kick yourself in the butt if you tried to cut corners on a job like that if something else went south. The biggest part of the job is taking the engine apart (Just ask me ) If you've gotten this far, don't short yourself. Remember, to pay for head removal once and fix everything is still less expensive than head removal twice and fix the stuff you skipped the first time around. There are circumstances where it makes sense to cut corners, however, this ain't one of them. "Measure twice, cut once", (ancient THIS OLD HOUSE PROVERB)