Some type of twin is good, but the air may not be.  It may give too coarse of a droplet size and not provide as good of a coverage.  I like an average droplet size of 250-300 for fungicides.  I would look for a twin tip or cap to accomplish that at the water volume you want.  I spray 12-15 gpa on wheat.  The tips I use are turbo tee flat fans -- two of them in a forward backward twin cap.