Sorry, RD, but I'm not giving up just yet and you can delete my posts if you want to. Or ask me to and I'll be happy to oblige. 
Now we're back to Ross/GG after you beat me up about it at least twice. 
That's okay though, I can deal, so on to the main reason for this post.
David said: "Now here's the "new way of thinking" I was referring to earlier in my post: namely, the green track that's largely hidden remains at elevation level ZERO throughout much of the plan. It's the OTHER track (in blue and purple) that is either elevated (blue track) or lowered (purple) to adjust ."
And you responded with "Also I believe it was you who mentioned making the second level the O elevation and raising the top level and turntable/roundhouse area...another hit as far as I am concerned."
So, lets say Level 2, the green track, is set to elevation 0". That means Level 2, the purple track, only has to decline 6" (or 7") to the point where they cross each other. If you run both purple tracks around the outside, that point can be quite far and the decline quite acceptable.
Now, that's great for Level 3, but what about Level 1? The green tracks are directly below the turnouts outlined in blue. That means if the green tracks are at 0", the blue tracks have to rise to 6" at that point or trains won't clear. If you start the incline somewhere on the green tracks, that means the blue tracks then have to rise 6" before they get to the tracks outlined in red. I don't care what level is elevation 0", there has to be 6" of separation at both the blue and red points. You simply cannot get there if all the green track is at elevation 0". There is not enough space for the tracks to rise 6" between the blue and red points. Things work in the original photo because it has a full 40' of O scale space to work with and the lower loops are drawn tighter.
Now, if you consider the green tracks in the red outline to be elevation 0" and the blue tracks above them to be elevation 6", then the rest of the green tracks can go down a portion of the total grade and the blue tracks can go up the rest. Unfortunately, then the purple tracks have to go down further because there still has to be 6" of separation where the green tracks cross over them.
If you and David don't understand this now, then I'm the one who surrenders, I don't know how to explain it any better.
