I don't know if there are sqwds big enough for your set up. Last I heard they only make 1/2" ones. As far as the switching valves, I'd post something on the DIY forum on reefcentral; I'm sure you'll get tons of responses, or just do a search. Probably McMaster-Carr has the valves.

I've never heard anything about reliability issues with the sea swirls; but they are pricey.