I've got a 4630 with a 300 gallon tank on the front that I use for ballast.  I also have a 300 gallon tank on the 3 point with a 42 foot manual fold spray boom mounting to the back of the tank.  I am planning to take the 42' boom off and mount a 60' Bestway brand in its place. I have never had problems with the tractor or 3 point lifing or handling the current sprayer setup.  I am a little afraid that the heavier, bigger boom may be a different story.  I did some research and found that the lift capacity of the 3 point is about 5260#.  I weighed the 60' spray boom and it weighs about 1350#.  The tank and frame Iam guessing to weigh 1000# (probably a little high, but trying to stay conservative), and 300 gallon of water weighs about 2520#.  The total of that is about 4870#'s.  Am I asking too much out of the 3 point?  I know weigh ratings depend on how far out the weight hangs. 

Thoughts please.  Remember I have a 300 gallon tank out front for counter balance weight.

 I have rolling terrain so that may factor into workability.