Thank you so much, Lugia, for your comprehensive and detailed suggestions that I have integrated in the new rack below. You helped me in a previous thread to set up my very first modular around semi-modulars and sequencers I already own. https://www.modulargrid.net/e/forum/posts/index/3864
This current thread is just (at this time) a mental exercise, though potentially achievable later within a second rack (end of the year?) The reason is I recently rediscovered Suzanne Ciani works, including the Buchla Concerts 1975, and I'm mesmerized by this music!
MScale is paradoxically included here due to the Mother32 already on my desk.
I finally swapped the A-138s for the new Make Noise X-Pan which apparently seems more in the quadraphonic philosophy of the Buchla universe.
PS: the RackBrute depth could be a bit larger. "53mm on the upper part (power bus) and 75mm on the lower part (no power bus)". https://www.arturia.com/faq/rackbrute/rackbrute-general-questions
But I'll verify that point very soon (delivery is scheduled for next week...)
'On ne devrait jamais quitter Montauban' (Fernand Naudin).