to make the 16" practical, you'd need the height adjustable monitor or it will overlap. In my case, I have a nice glass and steel riser for monitor but I also used the MacBook Pro box to increase the height of display temporarily. The MBP box is the perfect height to make them both fit. I see you can get 4.2" more height with the adjustable stand so maybe thats a good idea for the 16". I jsut didn't want to spend $400 on that, knowing ill always keep it at the same height
Yes I use the MacBook keyboard and trackpad. I also have the full size magic keyboard and trackpad but I have a heard time using it since its all too big and I prefer the trackpad under keys without moving hand. The MBP layout if more convenient and solid without moving around. Also I enjoy using the 16" inch screen and can look up and down with eyes only without moving head. I can play a movie on 27" as I do something on 16" or I can reference 2-3 documents without moving head around. I have other monitors but I don't use them in this setup because its just not practical and I've tried to make it practical so I often wonder why people would invest in such a setup. The only thing I can think of is someone having stocks open and dedicated to that side monitor for quick referencing.
I programmed the F keys to jump through desktops. Each F key has its own program. I find this to be more convenient in this setup than to have additional monitors.