Well, I suppose we are both assuming he is using two different fuels/tunes. If not it’s as simple as a higher boost target on a switch. I’m assuming now though that even the 501 tune is on pump so it’s all the same map…just more load.
But, if the second map was required for an alternate fuel, that’s exactly what I mean. With one trigger you can effectively raise boost, control timing and fuel. Using the nitrous table would be the cleanest way of doing this as you wouldn’t pressumably retune the whole map. Assuming the car is tuned via boost compensation you wouldn’t likely even need to retune fuel (assuming you were still using gas at various octanes and not meth or nitrous or your turbo was horridly inefficient at lower boost)