Hunting around in search of info and a vendor for the Clack 5-Button valve, I find a manual simply calling it the WS1 and photos of the WS1CS which has 5 buttons. Are those one and the same? If not, how different?
I might not concern myself except for two things: 1) 30 years in test engineering has on plural occasions beat me over the head for a trivial difference; and 2) plural sources now, including Ozotech's own customer help, have specified the 5-Button Valve.
That said, Ozotech furhter acknowledged that the EE board could be made work to equal advantage, but in the same sentence implied (without any specifics) that the re-config/adaptation (or whatever) was somehow tricky. If that involves wiring, no problem here. In my work, I modify electronics semi-routinely.