Ha! Yes, I saw the pool comments on the video site, amused me. I think the maturity of the water added character to the videos.
I agree, 40 degrees or even 45 would work for 4 - 8 feet depth.
I find making round lips rather tedious and difficult to control symmetry, but it is just a matter of taking care. I design all my lips with square lips, it doesn't make much difference, but many better fishermen here would disagree.
Frequency of the waggle is all about lip width; narrower = faster.
Videos 3 & 4 look like a tow eye position problem. The lip length and tow eye are a matched combination. You might be able to fix by simply trimming the lip shorter. Having your own test pool is a big plus. Gradually trim and test, and make notes of the changes.
As mentioned by others; symmetry is important and could be your problem. I stand over a square tiled floor to examine by eye. Place a 6" rule across the flat of the lip, this will magnify any angles that might be causing problems.
Dave