Wow, it's weird reading things I wrote so long ago!
That said, I truly miss SAW+. It had the most dirt-simple "screenset" implementation evar. SHIFT+F-key saved a layout, F-key recalled it. No lag, no crashing. And it instantly allowed 12 layouts of EVERY THING. Screensets now, even like I wrote all those months ago, are buggy as heck. They lag, they hang, they are just a total pain. Plus the weird "you don't have to save" BUT "you have to be IN the new screenset when you edit" is completely backwards.
All that said, the obvious definition is: plugin UIs in one tabbable window, different editing views in the other. It's extremely obvious, even WITH inline PRV (never use btw), console view (also never use, get over it, it's a dead medium for folk who can't let go of physical hardware...and I say that having learned on them), and all the other views. One last thing: MAKE THE PRV ABLE TO ROTATE 90 DEGREES! Studio One can do it, and it makes ALL the difference learning parts since a piano keyboard goes left to right, not bottom to top.