If there is one application that track tractors excell in is the grain cart.  Tweeking the spout by turning the steering wheel is NICE!

I do think you'll get more pull on your NH3 bar from tracks, though thats a good size bar for the hp your talking (no matter what the color) around here in this dirt.

Not sure, but if your planter is less than 44', you might like the rubber doughnut undacarriage better.

No matter what ya buy, make sure your dealer likes what they do!

Good luck