Re: How much training per week?
In his cryptic and near-religious way, Koichi Tohei says "extend Ki all the time". If you tend to view the Ki-Society bit as peripherally focused, it's easy to just put the "all the time" down as one of those sayings. However, most of the the very high-level practitioners of martial arts that use "internal strength" that I've ever seen tend to mention this "all the time" aspect of their training. You cannot really learn to move "from your center" with 3 practice sessions a week while doing "normal movement" the rest of the week. You have to practice all of the time in sourcing your power from the ground through the hara (or from the weight of the body) before the mind will ever take the clue that you intend to override the natural arm and shoulder inclinations we've developed since childhood.
O-Sensei had special heavy-weight garden tools made and reportedly did a number of other things which indicated that his practice extended outside of the dojo. I've listened to experts say that they even spent time stirring the soup with their middle, openning doors using the force from the ground, doing everything in fact, with the correct movement. So my 2 cents is that how many times someone goes to practice during a week doesn't quite cover the subject.