What id do if they can't mix 205-110 exactly is just order a tin in from an IXELL supplier and give them the paint. If you want 205-110 exactly you have to use an IXELL supplier, as the pigments will be different otherwise....
Id of thought a 1/2 litre would do 4 x wheels, let me know if you want i can hook you up with some paint, just depends how bothered you are about it being exact.
Cheers,
Si @ SS