What kind of field? Area? What type of grass?
I can't advise too much on large sprayers as I use 3 Stihl back pack sprayers. I can tell you my set up. I maintain 3 lawn bowling fields and 6 residential accounts that I cut with reels. The bowling fields are bent grass cut at 1/4" or less with a 10 year old Jacobsen greens mower. My residentials are a mix of perennial rye and KBG cut with a 27" Tru Cut reel at 3/4" to 1". The Tru Cut has a Big League Lawns CheckMate roller mounted in the rear. I rent an aerator and verticutter 2-3 times per year--too expensive and not utilized enough to own my own.
My sprayers are loaded with Weed B Gone, Triazicide and a fungicide. All dry chemicals are applied with an Earthway spreader with a 100lb hopper. I use a LOT of fertilizer and Iron year round.
Bowling fields are cut M-W-F and the residentials on M and F. Residential owners are very wealthy and like biweekly service for a pristine appearence.
This setup works well for te amount of turf I take care of roughly 3.5 acres total. Large areas such as Polo, soccer, baseball, football, etc.; these would need larger machinery to take care of. I do all of this with one helper; any more and I would not be able to keep quality top notch. Plus, more work doesn't equate to more money as I am operating at peak efficiency.
Hope this helps--not a whole lot about sprayers--sorry.