I know i'll get shot but I will be running out of the box tyres . My kit was purchase used so I dont have anything other than whats in the car. I was thinking of using the Tamiya wheel spacers as they comes in 0.5 and 1 mm thickness and are also anodised.

So please suggest the biggest pinion I can run on that setup and then I will buy a few smaller ones for when the tyre diameter get smaller.