Hi Forrest,
but this sort of sliders isn't intended for greater loads, we built our first pen-plotters with them ...
For medium loads i mostly use bush-bearings and for heavy loads (as in my CNC) supported rails.
Here a sample of bush-bearing-sliders which i used for laser-plotters and what should be fine for a repstrap too:
The only bad thing - they aren't reprappable ...
Viktor