Considering that squats require knee stability, this would indeed be a decent activation technique. Jump/ballistic squats would be better for purposes of high performance mass training, though.
While rep quality in the max force training zone is the dominating factor for generating high performance mass, I'd definitely pay attention to that number you mentioned for balance.
How long you're able to balance will help provide you with a gauge of your neural capacity for a given day. The longer you're able to balance, the more likely your CNS will be capable of increasing its time in that max training zone Thibs discussed.
Hope that helps!