I’m no expert but I asked the same question on AT last year and the overwhelming majority said a bow is most efficient shooting at the top of its weight range, so 50-60 if you are shooting 60. There was some interesting comments about maybe shooting the bottom end would be easier on the bow though but who knows.
I’m also not an expert. Not even close. But from my understanding back in the day the limb pockets on bows were floating and it made the bow be inefficient unless the limbs were cranked down tight. So the idea was always to shoot maxed out because the bow would be most efficient. In modern bows, the design of the limb pockets is far and away better and that is no longer an issue. So the bow will be just as efficient turned down in poundage vs maxed out. However, the old habits die hard so the general idea that bows are better maxed out persists. But I don’t believe it truly matters anymore with modern limb pocket designs.
I was in the same boat...I like 65 lb limbs, but I went with a bowtech this year and ended up 50-60 lb limbs. I am debating about buying 60-70 lb limbs just to have, as I would like to eventually increase in poundage.
Just to add, I've been shooting 60lbs for about 15 years and have never felt the need to go higher. Everything I've launched an arrow at and made contact with to date has died. I'll leave the heavyweights to the young mongrels.
I'm not sure if that changes any responses or not.