Help! 4x4 conversion ratio head scratcher

[REStracTORATION]

Hi all
Right I'm wanting to get a front wheel size roughly pencilled into my notes but I cant figure out the ratios to give me an answer.

Tractor has no front wheels (well its a parts bin operation I'm attempting its not built yet still on paper)

Tractor in question
Mk1 165
Rear wheels tyre size: 12.4 - 32
Tranfere box: 4 wheel traction
Front axle: chevy banjo
Front axle ratio: 6.6>1

I've worked out for front wheels I either need I think?????
8-24
10-24

Possibly 8-20

The propshaft can be and will be made with a slip clutch either dry or oil bath type I'm not wanting perfect matched numbers but just somewhere

If any help can be mentioned I would be most grateful

Thank you

 

[forblue]

4 W/D slip factor should be between 1-5% front wheels drive faster than rear,
%slip = fwd factor x front wheel rolling circumference, over, rear wheel rolling circumference, x 1,015

 

[REStracTORATION]

4 W/D slip factor should be between 1-5% front wheels drive faster than rear,
%slip = fwd factor x front wheel rolling circumference, over, rear wheel rolling circumference, x 1,015

Perfect thanks I'll crunch the numbers