The only problem with using a 1" vs 1/2" belt is the ability to manufacture a pulley that would properly fit the shaft length of most commonly used motors. Obviously as pulley length increases, run-out error at the crown of the pulley is magnified if there isn't adequate shaft length on the motor to correctly "support" the additional mass of the longer pulley. Also, one needs to have adequate belt tension, and I think this might become trickier with the longer pulley.
That said, I think belt length depends on factors such as the diameter of your pulley, drive type (DC or AC), as well as motor pod design, turntable shelf design, and a host of other factors. I generally shoot for around 44" in circumference, but I also have been fiddling around with an idler pulley to increase wrap around the pulley and the platter simultaneously, so I've been trying to position my motor pod/pulley as close to the platter as possible, hence necessitating longer belt lengths.
My best advice is to cut a few different lengths, and listen for yourself. The differences will be fairly apparent - vibration suppression, available belt tension, tracking of the belt on the pulley/platter, overall noise floor, so-called "PRaT", etc are all affected by belt length. Good luck.
That said, I think belt length depends on factors such as the diameter of your pulley, drive type (DC or AC), as well as motor pod design, turntable shelf design, and a host of other factors. I generally shoot for around 44" in circumference, but I also have been fiddling around with an idler pulley to increase wrap around the pulley and the platter simultaneously, so I've been trying to position my motor pod/pulley as close to the platter as possible, hence necessitating longer belt lengths.
My best advice is to cut a few different lengths, and listen for yourself. The differences will be fairly apparent - vibration suppression, available belt tension, tracking of the belt on the pulley/platter, overall noise floor, so-called "PRaT", etc are all affected by belt length. Good luck.