Ideas for 'L' shaped layout - Model Railroader Magazine

IMHO you're trying to squeeze a lot of track into a small area. I'd go for one mainline loop of the highest possible radius (11" in this case). If you want to be able to run two trains at the same time, I'd consider doing a double-track mainline rather than one oval and one figure-8. This leaves more room for scenery, industries, yards, engine facilites, etc.

Since you're doing 'flat-top' benchwork, consider (if you haven't already invested in something else) using Kato Unitrack so you can test out your layout ideas in real space. Most of us tend to greatly exagerate how much we can fit into a given space.

BTW, you can always add Woodland Scenic risers under the Unitrack later to allow for scenery below track level like bridges over rivers, valleys, lakes etc.