Dual Belt Pulley System

I've been thinking about machining a new set of pulleys incorporating 2 belts instead of one for my CNC mill. I have found that if I miscalculate and try to hog to much metal, the belt slips and the cutter stops, either breaking the endmill, or marking up my work piece and knocking the mill out of tram. Not to mention I hate to hear the steppers trying to spin when everything is bound up!
Anybody had any experience, or found any solutions? I'm sure a dual belt pulley will place more stress on the mill, but would like to have some input before proceeding. Thanks, Gray Watts