Yah i agree with that but a 8N is alot bigger than 20hp-25hp and weights more than 2K pounds though at 70% split you'd have more weight on rear than the whole smaller tractor weighting in at 1700 or so#. My neighbor and papaw has a 8N and also pulls a 2 bottom plow. A 1 bottom plow with a 20-25hp is it i think around here.
I was simply using the hp as a measure of tractor size any tractor will pull a plow at a lower gearing vs normal plowing gearing if power became an issue. You all must live on a topsoil farm cause it takes some major kubota juice up here to get thru the hard pans.