That's a very nice box setup/layout.

Can I ask where you get your Din rail and connectors etc. from - I may have to look at something similar for my control box and also I have a 1970's horror of a lighting circuit junction box in my loft that needs replacing with something more elegant.

Regarding the VFD, the mounting orientation advice in the manual is likely because of the cooling fan, so its not blowing hot air over something else that might be susceptible to over heating (the number of times front to back and side to side cooling for servers and networking kit has been overlooked when buying kit for some data centres I have had to look into is scary).