How far out ahead of the ZTR's are you mounting the boom? I'm at 18" nozzle height, ground speed 4 mph, 6 (11003 nozzles not AI, @ 35 psi) (10' boom) and by the end of day have some chemical standing on locations of mower deck. Have looked at the 'screen' Walker has between deck /boom. Would like for all chemical to go to weeds. You recommendation(s) would be appreciated.