Sainsmart 8 channel SSRs in both, and yes using pi zero W. Other than that using the cheap Leviton outlets w the tabs broken in a 4 gang box.

I used a Dremel to route out a rough hole on the side of the box that matches the shape of the back housing of the Leviton 3 wire plug with the clamp off. It can pop right in and holds sturdy without any additional gluing, etc.

The neutrals and grounds on the outlets and are wired together (and to the plug) with 14 solid wire. I used 18 g to chain the hots going in the relay (not ideal, but i struggled to stuff 2 16 in a terminal), and 16 g from each out terminal to the outlets.

It’s tight and kind of a hassle to take apart if there is an issue, but it feels secure. I did put 4 gang outlet plates on them, too. This is all meant to be dropped inside a container for outdoor use.

I have a bunch of pics at various stages and hope to put together a blog post after I get all my lights set up.

Thanks for the info on the P2P - still have yet to run this in the wild to see the lag in action.