I would start with 6 colonies, as I consider that a bare minimum to raise my own queens, and try to work up to 25 to 50 colonies over 3 to 5 years if you want to really know the game.
12 swarms and cutouts my first year, 9 stayed in the boxes. 7 killed that winter by a spray rig that sprayed the hives directly. "Oh, so sorry!" :ws: Luckily, 18 swarms were trapped the next Spring.
My own learning curve was greatly accelerated by some older beekeepers, a copy of The Hive and the Honeybee, 5th edition, and going immediately into the 2 most difficult aspects of beekeeping - queen rearing and honey-in-the-comb production.
One friend, a sideline-business beekeeper, got into the game 3 years before me by purchasing 100 colonies (no previous experience). He said, "I really needed 3 years with 30 colonies before going commercial - just to really know what I was doing. Mistakes are expensive at 100 colonies."