One of the problems I found was that the supporting legs would some times slip, so this is how I got around it. Firstly I got rid of the plastic feet as a couple had broken, turned the inner leg upside down and welded(!) some stainless steel discs to them. I then drilled two holes in the outer leg 1/2in apart. Next I took the inner legs and marked them at 1in intervals. Putting the inner leg back inside the outer I chose the top hole to work from, slid the inner leg till I could see the first mark and then drilled through, moved on to the next mark until they were all drilled.
For the pins I took a couple of old wire tent pegs, cut and bent them into shape.
Now I can adjust the legs with 1/2in adjustments and when the legs are put away the pins stay in place and eradicates the possibility of the legs coming loose in transit [You must be registered and logged in to see this link.]
The single hole nearer the foot is for transit[You must be registered and logged in to see this link.] [You must be registered and logged in to see this link.]
The foot pad is for a motorcycle side stand.
Hope this is useful