@mijostyn -sorry about that-school starts tomorrow (I teach part-time) and there's always a lot of last minute stuff no matter how well prepared you are.
I bought the big Minus K bench top rated for a 250 lb load because I was concerned about footfalls in this old (restored) 1880s Victorian home. The building is a jewel, vibes like a Western museum downstairs, original wood, wainscoting, high ceilings, almost all the glass is original on the main floor, transom windows, almost all original metal guides, rails, latches replated, all indoor shutters disassembled and restored, etc. It's a cool house if you ever visit Austin you must see it. The fact that much of it is original is due to poverty of the owners during the 20th century. The house does have a storied history but I won't go into all that here.
I was going to build a separate outbuilding, but once we decided how to use the space, the upstairs "loft"- which is more modern, was perfect (and the cost and disruption associated with the outbuilding was more than I wanted to bear).
I did have a structural engineer look at it and he said no way on wall mounting the table- he said the walls would move even if he did a steel install (you know those hanging toilets-- they hang from a steel substructure that can take huge weight).
So, balancing the XL was a little tricky, getting the right level for the arm to do its thing is a little like dialing in VTA- you adjust an increment and check. It's actually a tiny adjustment that nails it.
The bearing- I know I researched this at one point, I think Franc buys those, yes, hi pressure (well, 65psi), the little Slientaire suitcase style was supplied with the arm, it eventually died (I gather they all do and it had to cycle frequently because the tank was small); I think got a 6 gallon 1/2 HP one, very quiet but it ran into problems, mainly having to do with not draining properly-- for some reason, Silentaire has the drain the top of the tank with an "auto drain" feature that siphons the oil/water out but they are finicky. (At one point a had a 1 hp 13 gallon compressor set up-- total overkill, it was also tripping a 20 amp breaker).
Now using an oilless custom job from the Houston folks--I think it was meant for a tattoo gun--it is noisier than the oil compressors and has a small stainless tank but a drain on the bottom. In my silencer box, it is dead quiet in the music room but if you are downstairs you can hear it thump when it kicks on.
Silencer box, above. More later if you can stand it.