You would need to check with a dealer for adding draft control. I doubt that it is available, but possibly. I have never seen aftermarket draft controls, but they might exist.
JD 8320 MFWD, JD 6415 MFWD, FEL, and cab, John Deere MFWD 4600, John Deere 4020, John Deere 4430, John Deere 455 mower, Deutz, and Gehl 4610 perkins skidsteer
I'm not sure what tractor you have but most tractors you can go back and add draft control to them. Most brands carry the same draft control they would put on at the factory.
You can add draft control to the L3710. I have had it and still have it on my International. I have little use for it even with boxblading. It can be very useful for some.