Getting a seat flying ag can be frustrating if you do not have an insider helping you get the first job. I would suggest getting your tailwheel and High performance endorsement now and take advantage of any opportunity to fly tailwheel you can while building time for the commercial. Glider clubs are a good place to look for flying opportunities. Many times they use Piper Pawnee and Cessna Ag Trucks for tow planes. Once you get the commercial you can banner tow and do sight seeing flights for the time building. Once again those two missions often involve conventional gear aircraft.
I would also suggest getting your A&P license. It will make you more marketable to operators and if you ever own your own plane it helps keep the cash flow on the positive side if you can do your own wrench turning.
While you are working on getting your certificates you should try to get a job mixing and loading. You will learn lots of good info working on the loading pad and it helps with the networking as well.
Check out this website as well.
Spray Plane Forum
Lots of good people in the ag industry there to answer questions. Just remember that the season is rolling in many areas and posts might not get answered right away.
Hope to see you on the loading pad soon.