In addition to experimenting with inner-tubes I put a wheelbarrow tyre and inner-tube combination on the dummy, too.
In the pictures you can see different set-ups of the spacing of the wheels.
The wheels can be punched hard. How hard depends on the inflation level of the inner-tube. There is a trade-off between 'squish' of an impact and bounce-back . If you want to go 100% all out on this good luck to you, as you need to work out the sweet spot on the wheel, (as it rounded). Also, even when inflated normally a rear cross, or knee, will find a connection to the core of the dummy. You could I think work out a way to counter this with a bit of experimentation with inflation levels..
There is a nice bounce-back from the recoil on the kicks and knees.
You need gloves to punch the rubber as your skin will be taken off by the friction. I had MMA gloves on which also had my middle knuckle covered too, which was very welcome as that too would pick up some skin-scraping.
Conclusion: This beats traditional dummy pads. This would take sticks too and cut out the noise.
It is harder to manoeuvre the wheels into place as the inner-tube creates friction. Your joints will thank you for this over time.