I stop when reaching level 11 (89.41-91.01) but have a feeling that I should not go this high for best build......maybe stop at level 9 or 10 to start on attribute #2
Sometimes it's easier to take your primary attribute to 90 and then stop training it. Other times you take it to 74, 78, 80, 82, 85...depends on your build plan and the player's position.
Depends quite a bit... example when You're going to start / stop multi-training, and are You going to include attr. #1 there. I often stop early at 6-7 gap even.