As long as you can get the front wheel on the point of lifting, you're getting max traction. If you're standing on the pedals, that's very unlikely so you can just keep shortening the stays until you run out of ideas (curved/split seat tube, flying gate, whatever) because you'll never get them too short. If you're going to sit down, longer stays help because you already have your weight too far back, but you only need to keep lengthening the stays until the front wheel stays on the ground, once you go past that you start losing traction because the front wheel is taking some of the normal load which you really want to be supported by the back wheel.
great post. well said.