As far as what weight, that totally depends on the calf and if you want it "finished". Some people butcher them shortly after weaning (not that I advise this). Each animal has the capability to reach a certain weight, depending on genetics, nutrition, & management.
If your "bull" is about 6-8 months old and weighs that, he should have the genetics to finish at 1200-1300#. But if he is 12 months old & weighs that, you might finish him at 950#. Normally, cattle grow to a certain point, depending on their individual facts, than they start putting on fat. So no one can tell you how much he should weigh for you to butcher him.
7-14 days is plenty of hang time. Enjoy.