The essential feature of the stand is that it should be secure enough to withstand the bowstring pull without too much deflection. This was achieved with long side support braces down to a large plywood base board which the user stands on or parks their wheelchair on. The limiting factor for the base is transport size.
Also as always and particularly with a potentially dangerous activity like archery risk assessment is important.
For some reason archery is a very popular activity and lots of people get pleasure and a chance to meet up at these sessions.