What PDU's would you recommend for 220V running the S7's?
These are good switched PDUs. Either only order factory reset PDU or 1 that comes with the serial cables so you can do a reset and set up IP and everything you want manually.
APC AP7911 Switched Rack PDU 16-Outlet 200-240 VAC
You can't go wrong with APC PDUs. Never had a single failure. They have tons of models so be careful to pick the form factor that you want with the power capacity that you need.
This may just be my personal experience, but you should avoid Tripp Lite. They're probably cheaper, but not worth it. I had a pair of them die in exactly the same way just a few months apart. Bad design resulted in a blown diode.