It's the kind of dolly where the car doesn't take the weight - it's all on
the
dolly wheel.
A hard wheel seems a bit brutal, but since the dolly will spread the load
over a decent area and I'm looking at 5mph, compared to the 50mph
impacts at the tailwheel during landing, I guess it should be ok.
If there was a case of a glider being damaged in this way, I think someone

should have heard about it?
I tried a foam filled wheel, but it suddenly developed a huge flat spot and

pneumatic tyres haven't worked for me at all.