1957 TO35 gas:
I plow in third low pulling 3-12" My uncle could plow in first high pulling 2-14's with MF35.
So there many be some differences in hp and gearing of the different models.
Also difference in ground hardness that is being turned.
I have used a 5ft tiller with my tractor and it did a great job in the lower gears, second low.
The little TO35 is a fine little tractor for the jobs it was designed to do.