Ditto with LushGreen. On big lawns, we use a Spyker 220 electric spreader mounted on a 3-point hitch (JD 445). Our passes are 15 - 20 feet apart. Never any streaking either. But keep in mind, we can 'tilt' the 3-point hitch "up" to cover a wider area. Since the Z-Max has a fixed (level) adjustment, I would stay with a 15 foot to avoid streaking. BTW we usually run our JD's over 8 mph when spreading. Problem is...it's too fast for spraying weeds due to safety & accuracy.
A million people attended osama's inauguration & only 14 people missed work.