Pay attention Grand Trunk: it is a very good, perhaps even great chair for bird photography. But it wasn't perfect. The problem was that on softer ground or sand, the chair sinks too much to be a stable platform. I'm not a heavy guy either - 5'10" and 185.
I fixed it though. I bought a second chair, carry just the extra chair seat, and removed the plastic feet from the legs. In this way I can attach the second seat to the legs for one big foot that will not sink. There are still a few issues: the extra seat will not fold up into the bag and it could be made from less material (and without the extra storage netting) for the lightest weight. If Grand Trunk were to manufacture and include a cloth foot for this application, while adding just enough dimension to the bag for all components, this chair would go to the head of the class - World Class.