Torque is equal to Force multiplied by distance. In other words, forty pounds of force at 1 foot from the pivot point is equivelant to forty foot pounds. Force, also, is equal to acceleration multiplied by mass. It takes 20 Newtons to accelerate two kilograms at 10 meters per second per second.

Let's assume that the propellor is spinning at a constant 10,000 rpm, and ignore wind resistance because we're talking about propellor mass. Because the propellor is already spinning, and we're ignoring aerodynamic drag on it, there is no force required to keep it spinning (besides the force needed to overcome the aerodynamic drag, which we're ignoring). Force equals mass x acceleration, and if acceleration is 0, mass is inconsequential.

However, if the prop is accelerated to 12,000 rpm, acceleration is no longer zero for the time it's accelerating, and mass is of considerable importance. Force, and therefore torque, and therefore resultant torque on the airframe, are greater for the heavier prop.

So, in laymen's terms, the airplane will not torque roll any faster or slower with a heavier prop. It will, however, experience more torque when revving the engine up, spool up slower, have more gyroscopic effect, blah blah blah.