We used to pull 3 12's with our 4000. Mostly medium to light soil, and never had any trouble. Probably would take 4 12's ok. Just be aware, that if you are looking at a modern European plow like a Kverneland, the 4000 probably couldn't put daylight under any more than 3 furrows. A three furrow model AB weighs in around 1800 pounds, and 8-10 feet out behind. I have a four furrow on my 7710, and with no front ballast, I can lift the front of the tractor with one hand when the plow is in the air. Front weight is a must. Take care.