Attached to the edges of the baseboard with 3x 3/4" screws, I’ve added a piece of 6mm ply that butts up against the bottom of the Y1 and Y2 axes to stop the chips being flung out either side and across the workbench. I might do something similar at the back, on the outside of the frame, but it’s a bit of a tight fit, so will wait until I move the machine - if I ever do.
No issues to date and have only run a wood job on the brushes so far,. I haven’t done large plastic jobs like PVC where it sounds like that static stuff rears its head.
In my setu, I would think any static build up discharges to the metal baseplate before it’s a problem. You can get static disappating brushes too. But I’m not sure what is different about them though.
The brushes are mounted into an aluminum extrusion profile you buy with the brushes. The steel backer of the brushes slides into that profile. There are a few styles of aluminum extrusion to choose from. For the sides I chose a profile that allowed me to mount underside of the rails and for the gantry I chose an extrusion that allowed me to mount to the back corner of the rail.
Now mounting the extrusions is where I made a concession. Since I didn’t want to take the machine to pieces to drill and tap for screws, I used VHB tape. If I need to replace a brush in the future, it will require me to take that rail out of the machine due to how the strip of brush slides into the extruded holders.
If you can pick it up that’s a Godsend…their shipping charges are unbelievable. I once ordered a bunch of bolts, washers, and nuts ($35 in goods) and the shipping was over $20! I called them and they lowered it to $7.95. They had raised it because they were shipping from different warehouses and each was getting full shipping charged…so they only charged me for one of them.