Thank you to everyone for the suggestions. I'm scrapping the thought of splicing the ZW-L outputs. I strongly suspected it was a bad idea.
I do have a Legacy Powermaster 360, so I will go that route, using a postwar ZW for input. Frankly, I suppose I could skip the Powermaster and just connect the postwar ZW straight to the rails at 18V. But I could easily see myself frying a bunch of TMCC electronics. I like the fast acting protection in the Powermaster.