If you fear the roller digging into the bottom of the slide, some manufacturers have installed hard plastic sheets where the rollers ride.
Due to some damage on our last slide, I installed rollers and a thin sheet of stainless steel under the slide for the rollers. Each sheet was about 10" wide by 30" long. It worked really well and I now notice my slide rollers on our new RV are digging into the bottom material. I will probably install another sheet of metal to protect it as well.
There are on-line sources for SS material that will cut it to any size you need and ship it at a reasonable cost.