I like pruning them in early spring. If you plan on making yours into a standard, I would suggest that you do it little by little. Where it is nice to clean up the interior of the plant, it's a stressor to chop out a large portion of the plant structure. I'm making one of mine into a standard. Maybe just a 24" patio standard. My plant is in its third year, (from a cutting) and I think it'll take one more year to finish it. The nurseries use a stake that is attached very firmly, I do it a bit more loosely. Sometimes I'll hedge my bets and let them form two "leaders" and once I feel confident that one is stronger and straighter, I'll remove the backup. During the summer months you can "rub off" any young unruly growth, that way the energy will go where you want it to go. Hope this helps.
