I sure have enjoyed reading it ;-). A job well done. Like you have I already referenced those other great masking threads.
Could you clarify on the AL BAR you used for the Horizontal masks?
What is the thickness and width? Do i understand correctly that you also used a U- channel and wood to stiffen up the entire bar?
Have you ever heard of 'delrin' ? It looks to be a nice material to use on the ENDs where the BAR rides in the H-channel.
Thanks for posting all the somfy info! It helps to have a list to reference. They have way too many options.