Hollow square tube is cheap and strong, but the standard sizes don't really slide nicely on each other.
PTFE sliders are an obvious solution, but keeping them in place on the inside isn't trivial.
The idea here is to drill holes from the outside of the sliding part and to slot PTFE buttons inside. I used a slug-cutting bit and a milling machine, but the idea would work just as well with a hand drill, pillar drill or mag drill.
The part of the button in the hole keeps it in the right place, and the "brim" carries the load. On this basis I think that my ratio of "crown" to "brim" is not ideal, but was set by the size of PTFE rod and the size of rotary-broaching bit that I had.
Making the buttons probably needs a lathe to make them from rod, or a router to make them out of PTFE sheet. so whilst it is "low tools" it isn't wholly a "hand tools" design.
I came up with the idea for making a motorcycle lift, a project covered in a too-long YouTube video.
Once the buttons are pressed in to place I spent a little time with a dreadnaught file tweaking the fit and ended up with a really nice action.
More buttons might help for longer cycle count applications, but for my use-case with a high torsional load and using it a couple of times a year I doubt that any but the very end buttons see any load at all.