Bench Setup for Shoulder Press

I’ve been experimenting with the angle of the bench on my shoulder presses recently, and I’m not sure which is more recommended…

a) level 8 is as close to a 90 degree angle as possible, but obviously is harder so I use less weight

b) level 7 is one level less vertical, and i can lift 4kg more on each side at this level.

But which is going to be more beneficial for shoulder growth?

I personally do B on SEATED shoulder press because my back arches too easily if I’m at a complete 90 degree angle. However, if I do military press (which just means standing) then I have to be completely upright. I go back and forth on which ones I do.