No, you did things exactly right- - - -up to the point you decided to use a non-piloted driver, and a BFH. The air driver makes dozens of hammer blows per second, and once the guide starts moving, it slides out a little at a time. Getting that first little bit of movement without galling or cracking the head is the tricky part. When I was doing a lot of head reconditioning, I kept piloted drivers on hand for all the common valve stem sizes and the oversizes we usually drilled them out. The air hammer was also used to install the new guides, with a shoulder or a sleeve to assure the correct installation depth was accomplished. On the heads without removable guides like small block Chevy, we used multi-flute piloted drills to open up worn guides, followed by a chucking reamer to take out the last few thousandths and assure the right press fit for replacement guides. I used bronze guides on most of the racing heads instead of the cast iron ones we ran on street engines. Then the top of the guide was machined to assure the high lift cam wouldn't cause the spring retainer to hit the top of the guide, and it was usually machined for a positive oil seal that locked onto the top of the guide. We did a massive amount of work on heads- - - -and won a lot of races when our engines could breathe better than the competition.
Stovebolt heads have such convoluted passages and so many right angle turns for the mixture and exhaust gases to negotiate that doing fancy valve and port work is like putting lipstick on a pig! It's better to build a stovebolt engine for lots of low end and midrange torque, not high RPM.
Jerry
