I had a third hole setting problem earlier last year and striped a couple. Bad calibration on my part, had it shut too much. Now I basically just keep it the same gap as how I have the other two set and no problem anymore. I tried screwing around with calibrating the way permagreen says too but it was a waste of time I thought. The biggest thing is to keep it 7 foot from center of pass to center of pass.
I used to have a PG Ultra. Which hole do you mean when you say "Third hole"? Far left hole?
If so, I am thinking it is the hole with a cable control. It is the hole that you close off on the fly to reduce or stop flow to the right when using the edge deflector chute.
On my machine, the pattern adjustment was changed by loosening the knob underneath and partially closing off the right hole.(Which controls flow of particles to the left.) I used to close it to about 1-eighth inch less than full open.
I used an eleven foot swath--calculated center to center. When spraying liquid I reduced it to 10 feet, center to center.
i do like going in circles but sometimes its so hard to see your lines by the time you get back to your next pass also when you get to the middle of the lawn you almost always have a pass left that will have your heavy side on its self right on right and left on left
Use a counter-clockwise pattern for the dry material, and you get a perfect, even application every time. Just line your right throw to hit the center of wheel tracks of the last pass. This will be a perfectly layered ap. that is why I love the 3 hole design. I don't care what anyone says, the one hole designs ALWAYS throw heavy to the center, no matter how they are adjusted. This is why if I was going to order a Z-Spray, I would have it built with a Lesco hopper.