Great build log, videos, notes etc. I had a wonderful time reading and enjoying the entire process.
One idea as a way to make your balancing easier, I use these small pencil erasers and attach them to pencils used to hold my plane up when working on the CG.
They are VERY low cost, easily available as are the pencils I mount them on. A small hole in a block of wood and presto, a very simple way to safely check your CG.
*** Sorry the image is so large, not sure how to scale it lower on this site.