SoftTouch Self-Stick Non-Slip Surface Grip Pads - (8 pieces), 1-1/2" Round - Black

Height is personal preference based on chair height and well, your height. For me while sitting, I keep my desk at 29in off the floor (from ground to underside of butcher block) so it’s 30.5in on the surface. For the Alex, yes I used risers flipped upside down mounted to the top of the Alex cabinet. Here’s the ones I used: Masendelk 2 Inch Metal Furniture... https://www.amazon.com/dp/B09QSYD17F?ref=ppx_pop_mob_ap_share I also used these on top of the risers to “grip” to the underside of the static block to prevent it from sliding around. The block is heavy enough to just sit on top without the risers having to be mounted into the underside of the block, but it was for extra security for my purposes. https://a.co/d/0aZE2JIy