Instead of leaving empty sections on the bottom warp for the stripes, I chose instead, even if I was affraid to end up with friction issues between both warps where each section crosses with the other. I wanted by doing so to avoid tension problems on the lower warp beam which holds maybe 4 to 5 longer than the top one. I also had to cut a new bunch of 60 warping sticks before starting.
Threading the heddles from two separate warps was no problem.
All looks tidy from the back. The double warp beam works as planned.
While I had planned to use 2/9 linen for both warp and weft at 24 epi, I had to switch to a 2/10 linen warp for a balanced weave. I did not want to reduce the sett and end up with narrower towels.