V12... Dave posted earlier of a Pro4 Spindle swap that called for the TC3 dogbones because they are Blue and the Pro4 dogbones are Purple. So Purple dogbones would look funny on a Blue car. TC3 and Pro4 dogbones are the same size. So to keep the car matching..........
6mm wheel hexes can be used with 24mm rubber tires. But the main concern for alot of people here in the states is running the car on carpet with 28mm foams. Plus it's also a Japanese Rubber tire EvoIV setup to use 6mm wheel hexes up front and the 4mm hexes in the back with a shim.
One side note though... when using the 415 axles and shimmed out... with 6mm hexes... the front width will be about 191~193mm. This is with C/A front blocks and foam and rubber tires. Perhaps with A/A front blocks it will be 190mm on the dot. I'd highly suggest using the Square Pro4 Ti Axles (non MIP) if you are worried about making the 190mm width rule.
Dang.. it's getting late... almost 5am here and I have to open up the track at 9am! haha... Oh well.. another late night working on the car the day before the race... when will I ever learn!
If only I didn't volunteer to open up the track early I could get some sleep!
Oh well.. off to bed. Gonna see how I do with 2° caster blocks and Pro4 Spindles in Stock and 19t....