I find .500 spine arrows appropriate for all the bows I would hunt with, from 45-51#, with arrows cut to 29”, and point weight varying from 150-200 grains, depending on what tunes best. I normally use .500 ultralights, so I can keep the point weight up and the overall weight down. When I used to hunt with heavier bows, I found that 54-56# was the crossover point to .400 spine, depending on the point weight I wanted to use.
For lighter weight bows I use for 3D, I use .600 spine ultralight shafts with 75-100 grain points, to keep overall weight down, as point weight is not a consideration.