hybrid and resmed

I was wondering--are there any hybrid users out there with resmed CPAP machines? What mask setting do you use? Right now I have it on the UMFF setting. My DME told me to have it on standard, but the RT at the DME told me to try UMFF. I thought of maybe trying Activa because the exhaust on the activa feels almost as high as the exhaust on the hybrid--so anyway--I was just wondering what other people use...
Thanks!! Cindy