Had to find my old machine design text book aka 1959 edition which has a closed form solution for this static case. When you start the saw then conditions change but if you so desire the loads can be calculated in a closed form basis. You are building your so you may need that info also?
You can program this in EXCEL and make as many calculations as you please. Of course you get strange results if you set up a bad case
L= 2sqrt(C^2-(R-r)^2)+pi() (R+r)+2 * (R-r)* arsin((R-r)/C)
C= distance between wheels
R large wheel R
r small wheel r
Make sure the arsin is in rads
Note site was not showing * properly it appears I got it fixed.