Eyeball it. We checked for plumb every few poles with a 2-foot level. However, they’re rough poles, not planed dimensional lumber, so we also stepped back every so often and took a glance to see if it looked right. This is one those times where the tool is a guide but in the end you trust your eye. It knows what looks right.
Outer Circle, Last Log. Since the poles I used varied in size from 4-5 inches or so, once I got to within about 2 feet of closing the circle, I did a mix and match of poles I already cut to see which combina- tion of heights and widths fit best.
Rock ‘em and lock ‘em. Make sure the posts are reasonably plumb first.
Level + eyeball = on the money.
Mix and match the last few poles to get a combination that works. Note that the space on the left of the photo is for the hose chase. I kept it open by leaving a pole loose.