I'm biased, but I think the best soil to use would be the gritty mix or something similarly durable and free-draining. Repotting, including root work, would be every 2-3 years. If you're only potting up, a good guideline is: pot up before the planting gets to the point that the soil/root mass can be lifted from the container intact. It's widely accepted in the nursery trade that plants allowed to progress beyond that point will exhibit limited growth and vitality on a scale closely linked to the degree of root congestion.

Al