I've set the chart according to the circle and 45 degree on the chart. They aren't perfect but they are usually within +- 1 degree. Just play the safe side of the diagonal or right angle. Channels like TXN can also work well if you can get a good LEAD point. I have published several different channel ideas also. Nothing guarantees the right diagonal is where it's going to go, but it's a good guess. The last 2 angles are reflections. I find the ratios I've been using are deadly accurate when the scale is manipulated to make them work. The wedge tool will anchor to 2 points if you get it on the 1st shot. Then just move the days bar left and right until the circles or arcs hit their points. Not all arcs hit 2 points on direct swings, but I try to set the chart up so I can get direct 2 point hits on 1 arc if the chart allows it. On strong up or downtrends, the direct swings usually don't work. In those cases it might be more like starting on 1 or .874 and go to the next 1 or 2 arcs higher or lower.
My ratios are inversions for the arcs, so the inverse of .764 is 1.309 and the inverse of .874 is 1.144. Sometimes double distances are used also ie. .618 to 1.236 or .5 to 1. My ratios are .382, .5 (or .472), .618, .764, .874, 1, 1.144 and 1.236. I prefer the higher ratios from .764 and up because I'm usually going for larger arcs on the swing. These arcs are very precise WHEN the scale is set right. I mean very precise. They show probable reversal points.
My ratios are inversions for the arcs, so the inverse of .764 is 1.309 and the inverse of .874 is 1.144. Sometimes double distances are used also ie. .618 to 1.236 or .5 to 1. My ratios are .382, .5 (or .472), .618, .764, .874, 1, 1.144 and 1.236. I prefer the higher ratios from .764 and up because I'm usually going for larger arcs on the swing. These arcs are very precise WHEN the scale is set right. I mean very precise. They show probable reversal points.