How much does the material you are trying to move weigh? Most of the time, this is a simple decision. Obviously, you don’t want to undersize your hoist, or choose a hoist that cannot safely lift the load. Another less obvious problem is oversizing your hoist. If your load is 750 lbs, why not just buy a 1 ton hoist rather than a ½ ton if the price isn’t that much more?
This may be okay, but if you do decide to oversize the overhead hoist you choose, be sure to keep in mind that a high capacity hoist may weigh more, or have a larger frame size that could prove to be troublesome when it comes to installation. Make sure you have the clearance and capacity on the support structure!