Maybe I'm late to this parade but I want to play too.
The old wisdom said one horsepower per inch of bottom.
Thats a broad statement and doesn't consider soil types but just FYI, I pulled a 14" two bottom with a
L3240 HST which has 25 pto horsepower.
PTO power relates roughly to Drawbar horsepower so...
Two 14" bottoms would require 28 horsepower. By those figures, I was slightly underpowered but my soil is sandy loam and I pulled plow reasonably well at a speed around 3.2 to 3.8 mph.
I now pull the same plow with a
L5740 with 50 pto HP and I can already see (tractor is not broken in yet so I haven't hammered on it) that I can run away with the two bottoms. I've pulled it 5.5 mph and still have some left. but that's a bit too fast.
Your tractor has 36 or 37.5 PTO power (depending on whether it's an HST or Gear) and a 3 bottom 14" plow by the old rule would require you to have 42 HP. Since your soil is sandy, I say try a 3 and if you can't pull it the way you want, drop a bottom as everyone else has suggesed. You ain't gonna hurt the tractor.
Just my $.03 (adjusted for inflation)
edit, are you two wheel drive or 4. I left that out of the equation. Two wheel drive in that tractor and a three bottom might give you a bit of a problem. Another thing, your tractor weighs about the same as my
L3240. I could not pull the two bottom at any reasonable depth in two wheel drive. I just spun. Good luck