Well, actually it would be 8, not 9, but 7 is so much more "me". And 8 & 9 go into 360 so easily... I think I used a 1/16 inch two flute. I'd probably go to 1/32 inch to make one in 1/24 scale. (Be sure to buy those in bulk...)
The kit's master cylinder, (it still needs a decal that I haven't made yet…)