I decided to build myself a seat as apparently I don't have enough projects on the go with Steels and Classic Cars.
So far I've built a box similar to dimensions I've seen on the forum and close to a friends seat so, looking pretty good there. I'm just building a simple seat with no side compartments although I may ad UK power to the side or back like the USA seats I've seen.
My next hurdle is to fasten the legs (which I've not made to length yet) to the "box" and make a locking mechanism.
The plan is to make a conventional U shape leg with the supporting rod that locks in the middle. My main problem at the moment is the steel conduit straps I found would let the legs fold beyond 90 degrees towards the outside of the box due to the screw on the strap.

Do most seats use the recessed edge as a stopper underneath? or does all the leg rigidity come from the central lock?
I just want to make sure there is no flex in the legs as the drum stool I currently use is bad for that.
I did notice this seat on the forum has a similar design to what I'm making with the current conduit straps.

The plan for the central lock I think would be to cut two grooves in something like this with a central bolt/wheel to lock it down.

Lastly I've noticed a few people have adjustable feet on their stools. Is there a place online to get these from? I think the leg tubing I'm using is about 22mm but I need to check.