Hi there! First, you might want to check out what 'the master' of open tunings uses. I would say that is 'Don Ross' (Canadian, eh? Yay!).
Check out what he works with and fiddle about. I learned to play (in an Open F tuning) his iconic piece, ''Berkley Springs".
www.youtube.com/watch?v=xTE5aCiqMkY Here's a link to his site:
gobyfish.com/Tunings.html But one he's not listed is one I've been having tremendous pleasure working with. Try, 'DGDGAD' (pronounced, "Duhg-uh-Du-Gad" ... okay, I made that party up).
Try it with a capo on 3rd fret or higher for nice and accessible variants with the C major switch. For the most part, you'll be playing in G major, but D major is possible too (and minors of both are an option - it's a very flexible tuning!)
Best to you,
As Always,
FR