I don't work with nor play with Z-scale trains. I can hardly see them! yeah, I know, it happens in the best of families.
About the neatest and most fool proof Z-scale layout I have seen was in a rather large coffe table under the glass. The train was propelled with an air pump and tiny holes between the ties. It seemed to be very consistant at all speeds due to the fact the builder had prepared the bottom of each car to respond to the air stream.
Switching was accomplished with toggles in an opening in side of table that ran tiny cables to switches.
This same fellow built another (they were all built for customers) layout in a coffee table which was also air driven but had the catinery (never did like that word) and all the works of an electric.
These trains would only travel frontwards of course but I was impressed by the simplicity of the whole scheme.
This person was quite a craftsman but non of this is outside the realm of most peoples abilities. And the price is right if you do it yourself.
I do not expect a royalty or gratuity for furnishing this idea but you know, times are tough.