All Type A fibers unless you train for an endurance sport!
Disagree, doing very low weight, controlled and high repetition (30-40) IN ADDITION to moderate and heavy weight is the way to go.
Those high repetition sets have been shown in studies to help increase capilariztion (small blood vessels being formed) in sollicited muscle. In turn, those new vessels can help deliver nutrient and cleaning wastes in the muscles. It basically helps creating satellites cells around your muscle, hence helping hypertrophy.
And actualy, type A fibers are slow oxydating (endurance) fibers. What you would want is transform type IIB (fast twitch) into IIA (medium twitch) that have a greater potential for growth, but YOU WOULD LOSE POWER (A TYPE OF STRENGHT) IN THE PROCESS.