Can I use sona masoori rice for making dosa?
@tcb,  I have successfully used sona masoori rice for dosa batter.

try this method:

Preheat oven to 200 degree F. Then turn off the oven. Then put your batter-pot in the oven on a tray.Check after 5-6 hours. If temp are really low outside, and you think it is still not fermenting ,again turn on oven for a couple of minutes and turn off. Batter should be ready in 9-10 hours.