I think you've come up with a great solution. And should you need more space for a given project, you could move one machine aside and have all that table space to work on.
I was just about to ask you about the walls as they look pretty, kind of like a marbled fabric... Then I realized that it might be insulation with plastic tacked over? If it is - well, lol, I still like how it looks!
Do hope you are able to get that Janome to behave all of the time instead of only when it's feeling cooperative. Darned sulky machines!