I don't have any experience with slide rollers on a Schwintek slide system, but my previous camper (a Lance) had the Schwintek, and in my research on that system, the rollers are under the slide with no access unless you slide the slideout all the way out..
Here is a link to the slide system manuals from Lippert:
I saw a YouTube video where a guy added additional rollers, and it is done just like the Accuslide system, where the roller is on an L bracket, and you simply lift the slide enough to put the rollers under, and they mount to the outside edge of the RV. I would think you'd need to be very careful about height of the rollers so you don't strain the rail guides.
There is also an aftermarket drive system for the Schwinkek, a much beefier system with heavy duty gears and rails and other major components.