This is an interesting pattern.
The issue with the short section of frame supporting the bend from the long side to the crosses is also interesting. I will comment on this once I have seen more members opinions.
At the moment I think that there is a tiny problem with the starting method though.
, you do address the issue that the second main on the right is not at reference tension. However it is a bit more complicated than just having 3 strings (2L, 1L & 1R) at reference tension and 2R at something less than reference tension.
You have remarked that there will be friction between 1R and 2R at the head of the frame. This is definitely correct. However, this grommet/string friction/sliding is not enough to stop zero tension loss on string 1R.
Instead of (2L, 1L & 1R) being at reference and 2R at less than reference, it will be:
2R is less than reference. In fact it is actually at less than reference plus whatever tension is gained from the string sliding back towards 2R from 1R.
1R is at reference minus whatever tension is lost through friction/sliding between 1R and 2R.
1L is at reference minus whatever tension is lost through friction/sliding between 1R and 1L.
2L is at reference minus whatever tension is lost through friction/sliding between 1L and 2L.
Obviously as you install more mains on the left, the tension gets closer and closer to reference. The fact that you are also using a constant pull machine will make the above observations even smaller. Also, the type, shape and surface coating of the string will have an effect.
One simple solution to counteract this is to set the right hand side fixed clamp on the 2R string at the head of the racket before pulling tension on the 1R string from the throat.
This is something you have already addressed in previous videos of yours. You describe it well in your Yusuki method / Starting clamp video at 01:50
I know that this is an incredibly minor thing, which probably in practice has very little effect on the overall stringjob, however the very same thing was pointed out to me by stringers that have decades of knowledge on me.
Please do not take the above as a criticism, it is something I thought would be interesting to share.
Also, when I get more time, I will make a video of my starting method which I have not seen posted on TT yet.