So here is my big question. when is pruning no longer helping my plants?? I have 3 plants on the go, 4x6x8 room, one 600 watt HID MH bulb, hydroponic recirculation program with General hydroponics Nutrients. I am experimenting with different pruning techniques. One plant I am trying to get very branchy (lots of topping) one i am trying to prune away most of the lateral growth, and the other I am trying to keep shorter, get 5 main colons, then top and prune away all lateral growth past the first bud sites. I started my flowering light cycle about one week ago. How long can I keep this up before i'm doing more harm than good. I usually prune only a bit at a time to let my plants recover. If i'm topping 2-3 weeks into the flowering stage, will i just be wasting a good bud site???

Unless you just want to reduce the overall size of the plant by triming side and lower branches. I would only top my plants at two weeks into veg and leave them alone after that. If you top them too late in the cycle they will not have time to recover and give new growth.
If you prune 2 or 3 weeks into flowering you will only reduce your overall yield. If your triming to reduce size and bushyness then you can prune anytime, but again if you prune during flowering yield will be lessoned.
That is my humble opinion.
Good luck