Pull a 30' Salford at over 10mph with 400 horse 4x4.  Doesn't even know it's back there.  Probably could pull 35', or maybe 40' at a little slower pace.  Have pulled it with an 8430 Deere MFWD, puts a bit of a load on it.  If I were to two pass, I would do one at an angle and probably the pre plant straight to give you smooth planting.  If there was a place you had to run a field cultivator through, you can get through just fine after one pass.