[Al_The_Man]

Adding a belt and pulley or any gearing will reduce the amount of power you will be getting at the load.
Gearing has losses so if the efficiency of your gearing is 90% then you will loose 10% of the input power to heat.
.

I am not sure I follow this? The torque will increase by the ratio of reduction, e.g. for 2:1 your torque will double, even if you lose 10% in efficiency, your torque has increased to almost double, besides that your load to motor inertia ratio will will be reduced by the square of the reduction, for 2:1 this will be reduced by 4.
The industry recommended target for this is 10:1 or less.
Al.