In your opinion...

[Bonkey]

How much weight do you think a shetty / cob cross (11hh) could manage for a short gentle ride?

Obviously thinking small adult here...11st too much ?

Pony is stocky...wouldn't be anything else with that breed mix

Yep that does sound too much for a little pony

I would say more like 9 stone?

20% of the pony's weight as a maximum

Far too much.

9 stone absolute tops if the rider is well balanced and you absolutely have to.