I'm a regular GDAE player live, though Andy (singer in Brother Crow) uses the DGAD tunings.

I was speaking to Jez Lowe who uses open G (GDGD) and open D (ADAD) tunings...I've been giving open G a whirl on my flat top mando, and it's a lot of fun, though as I said, I'm more comfortable with regular tuning on the carved top.

Try the following website, which I always found useful:

http://www.nigelgatherer.com/

All the best,
Graeme,
Brother Crow.