I have to agree with the wider curves, I also have a lot of "big iron" including the VL-BB, several Challengers, and other scale articulated locomotives. I have a smaller space than you do, and while I have some O72 curves, most of my curves I tried to to larger, up to around 99" diameter. Mine is a folded dogbone on two levels.
Since you have AnyRail, I attached the plan so you can take a look.
The 3D image of the layout.
A couple of shots of the current progress. Most of the main level track is down and up the grade on the right. The second level will be over the first level loops in the foreground, I have to get all the wiring completed for the main level before putting that back on.
What the second level will be when I put it back together, hopefully in a couple of weeks. It's fabricated, just had to remove it to finish track work on the main level.
