GMMAT, you asked me how, friend. Of course you select a 45# bow and a stiff 250 carbon, the relative ends of a spectrum. Think locigally.
The original question, was about shooting one arrow with different length bows. Simply...you tune your bows to that arrow if that arrow is already in that spine area. They didn't ask about spining very stiff shafts to light bows.
You can actually do more to a bow, than an arrow, to accomodate this. It can start with simple string adjustments, and go to stick on, or even adjustable rests with plungers, etc. That's tuning the bow, and is not complicated nor unattainable.