Decided to give acetone a go - and it works pretty well.
Made these very simple but effective acetone vats from cut off 2 litre bottles, rubber bands and bits of carrier bag. Works fine. The best bit is how it keeps the tyres out of the sticky gunge of the old acetone at the bottom in the "feet" of the bottle.
I did notice that the tyres at the bottom of the stack are seem to be ready sooner, but the fumes definitely go everywhere in time...
Cheers,
Ty