Hey, you guys are da best! FINALLY got the head off the block. In case it helps future searchers:
0. liquid wrenched all head bolts a week prior to trying to remove them
1. removed all studs possible with double nuts (had to use shallower grade 8s from the hw store to get enough thread engagement on top nut)
2. removed stubborn studs with Craftsmen bolt extractor--designed to grab rounded bolt heads, but worked incredibly well on the studs, even super tight ones (destroys the threads, though)
3. despite two studs remaining, worked with the rope method (stuffing about 10ft of 3/8" nylon rope into cylinder through plug hole, then turning flywheel) quite a while on cylinders 1 & 6 until both ends of the head moved just enough to see a sliver of light between the head and block--however, head still would not break loose with two studs remaining (btw, I did not use the starter to turn the flywheel since I had already taken it off & engine was out of the car so would have taken a while to wire it up... just used a socket wrench on a flywheel bolt and spun it as hard as I could)
4. then got one of the two remaining galled studs out with the bolt extractor by using the hollow handle of my floor jack as a cheater bar! (I know, not generally a good idea, but I was desperate after spending two days on this)
5. tried same technique on last remaining stud, broke bolt
6. hit side of head with rubber mallet until it started to rotate, then used the head itself as the means of unthreading the final remaining bolt from the block
Unfortunately still have that broken bolt in the head, but at least part of it sticks out on the bottom. BTW, those bolt extractors that grab the head of bolt (or in this case threads) are amazing--the bolt broke before the extractor slipped.
Thanks again for the advice. Much appreciated.