Spraying tractor

I'm considering updating my sprayer tractor. Currently I'm running a John Deere 4555 pulling a Top Air 1200 gallon sprayer. I'd really like to go with a John Deere 7930 with an IVT. Is there anything I need to look out for that are common problems? I like the 7930 because it is lighter weight than an 8030 series Deere. It is also still small enough to run a baler if needed. I am wanting more horsepower because when it is soft the 4555 works to pull a full sprayer and some day I might get a bigger sprayer. Is anybody else using a 7930 spraying and if so how do you like it? Also, any recommendations on front tire sizes for ride quality and flotation? Currently have 420R28 on the front of the 4555 and if hardly ever breaks through soft ground. We have a 7730 with a power quad already for baling and feeding and I've gotten spoiled by the size of the cab and how quiet it is. Any advice and suggestions are appreciated.