Re: How many frames?
Think I haver taken some 30 frames from a strong second year hive and they haven't skipped a beat. Am limited in height to 5 deeps and periodically removed frames so they had open cells for brood and nectar storage, so they wouldn't swarm. I remove any 80% capped honey frames and move frames to weaker hives and stat NUCs, just to keep ahead so as to provide open cells. Harvest the honey and reinstall wet frames.
Removing brood and providing open cells and frames to draw helps to curb the swarming impulse.
They still have 5 deep supers pretty well packed with nectar. Queen is starting to ramp down. Air humidity is high and bees are having troubles bringing the water content of the honey down.
5 for a NUC in May
5 for a second NUC in July
20 frames of nectar and honey
The key is to do it periodically and small numbers of frames each time, and they don't skip a beat.
And I don't want to talk about my second hive that came through winter stronger than the one above, but I've had never ending queen problems.
If you always do what you always did, you'll always get what you always got!