I moved the shooting rail upright support bars from the rear of the seat to the front of the seat. It made a noticeable difference to stability, and the "depth" of the rail now makes more sense as you can rest your weight on it.
The height adjustment is a real faff though. I try to leave it friction tight as the adjustment knobs shear off.
The seat is 2 hours from home. I'll post a photo of the adjustment when I can
I did treat myself to 2 of the bushwear galvanised double seats. They are rock steady. I added a length of light d rail to the bare box section shooting rail to make a more comfortable shooting rail. I've had no luck with pipe lagging over the years - birds seem to find it makes excellent nest insulation!