Actually, I did both. I dropped the handkerchief first, before downloading the app. Then I couldn't find the handkerchief LOL! Then I downloaded the app yesterday or the day before, and we decided to go map out the line today since it was windy, and we assumed that would keep the mosquitoes off us a little better.I had been wondering where you had gotten off to. Happy to hear and see you found the corner and happy to be of help. I have used OnX when hunting antelope in eastern Montana where ownerships are confusing and the fences aren't even on the property lines (open range). And hunting white tails in western Montana where the property lines are like yours.
So, did you do the flag drop thing with your drone or just go crashing through the brush with your GIS?
We walked pretty much straight South from the back of our house, and up the hill behind us in the woods, using the app. When I got to our property line, I wrapped a piece of logger's ribbon around a tree, and then worked our way East. The handkerchief, and the GPS point you gave me were within about 5' of each other, and 10'-15' from the rebar! So, actually, all three methods worked relatively well. Your GPS coordinates, in conjunction with my drone drop, the post that was already there, and the OnX app.