I really need to learn how to use scarm, but until then, here is an idea for you that adds the double reverse functionality, while maintaining the same feel and adding a siding or two. The accessories may need to be re-situated (such as the 397 coal loader switching sides of the coal ramp). In my drawing, yellow is your existing plan, black is new idea plan for you. I'm not sure of how the spacing would work out for the accessories and that's prob the hardest part. As Dave mentioned, it's not the end of the world if you have to go backwards through the reverse loop to change direction as in the current plan.
You should be able to get by with 1 ZW. Outside mainline on right handle, inside switching on left handle, accessories (low voltage) on B and accessories (high voltage) and switches on C.
If you want to add a second level, the simplest route is to add a separate oval by itself about 7-8 inches above the table top. A lot of the postwar display layout do this to add that dimension to the layout. Might be difficult to situate on your layout being action packed with the main focus being on accessories. An elevated plywood roadbed with some 1x4s for support would accomplish this.
Here is a good resource for connecting power to accessories among other things. I refer to this a lot: https://ogrforum.ogaugerr.com/...ruction%20Manual.pdf
