Think of the ZW-L as 4 channels or banks of power, each having a PowerHouse and a PowerMaster.
The plan really only has two Power Districts: 1) The Outer Loop with Passing Siding; and 2) The Inner Loop, Reverse Loop and Yards.
These only require 2 channels of the ZW-L because you probably wouldn't want to run more than 2 Conventional trains at any given time. Alternatively, you could potentially run 4-6 Legacy locomotives simultaneously with 2 ZW-L channels connected in this way. You can even mix and match, Conventional in one Power District and Legacy in the other.
These two Power Districts can be further divided into Power Blocks as follows:
1a) Outer loop Mainline
1b) Outer loop Passing Siding
2a) Inner loop Mainline and Reverse loop
2b, c, d, e, f, and g) each Yard Spur individually
If you look at the suggested changes I made to your track plan closely, you'll notice that each of these locations has a 1-3/8" isolation piece.
If you're only using Legacy, all of these Power Blocks can remain powered all the time.
If you also want to have Conventional Loco on the layout, then each of the Power Blocks can be turned on or off individually with switches as needed.
This leaves you with two remaining Channels on the ZW-L that you could use for Switches and other track accessories.
