I have several f-12/14 and plows, and have done many a plowing with them.
My grandfather bought a f-12 with a single 18" bottom lil' genius back in 1935. He farmed 80 acres with it along with a team of Morgan horses. We have sandy loam, swamp land, but very little clay. I rebuilt the tractor when I was 12, and I am still plowing with it in third gear on the sandy loam, second in the swamp land, and first in heavy clay. I like to use this plow for deep turning or sod busting because I can drop it deep in the ground.
I have pulled a double 12 with this tractor in sandy loam in second with ease. There are no special pistons in the tractor, nor modified carb, just the same OEM style parts. I do put in about a quart of kero-or-diesel-or-fuel oil for every 5 gallons of gasoline to make up for the lead removed in the gas and keep the rings from sticking when they sit.
I do have a triple 12 plow, and tried it once behind a f-12. Best I could do was first with wide open throttle in that sandy loam.
Now you can have a good tractor, but if you don't set the draft lines right, you'll loose traction, waste horsepower and it won't pull s!@#. If you can get a hold of a McCormick Deering plowing handbook, it is very valuable in setting your plow up right.
Keep in mind that comparing an H or M to a F12 is like comparing a f350 to a f150 in towing a goose-
neck. The F-12/14 is a great little tractor; it was designed to be smaller than a regular/f20, and is comparable to having a team strong Morgans or light Percherons (Draft Horses). I know this from personal experience working with both. The tractor was also priced lower for the small farmer (20-75 acres)to afford. I have regulars and an f30 and if I need the horsepower, I am happy to use them. The f-12's though are very economical on gas; even with plowing.
The right tool for the right job....