Jeff, if you are modifying the steady rest permanently, no easy return to the brass followers, then I suggest you consider it for a while first. Roller steady fingers certainly work, and lots of machinists like them. They do, however, roll on the work, which doesn't rub on the shaft (usually,) but it can crush grit into the work. The ones that rub can also have problems with grit getting under the fingers and then scratching the O.D. of the work around the circumference. The smart thing is to start with everything quite clean, and then keep it clean by keeping the swarf away from the fingers. That can be done with a larger piece of cardboard with a hole to slide over the work shaft, big enough to keep the chips and grunge from reaching the steady and the work. Both styles of fingers need to be kept clean and well lubricated while the work is spinning, even more so as speeds increase. FWIW, I like the brass tipped ones better, especially on softer work, like aluminum. I find them more multi purpose, and perhaps a little bit more rigid because they can be snugged down tighter than the ball bearings like, to help control chatter. The best answer is probably "both" if that is possible, and without compromising either.
Edit: the roller fingers can also take up space so that it effectively makes the maximum shaft size that will fit in the steady smaller.