I took this in Kathmandu just a couple of weeks ago. The butter candles are amazing. They are both great light, and a challenge at the same time. The light they put out isn’t incredibly strong, but adds up as more and more lights are lit. They do create a gorgeous light though.
I tend to shoot these on manual. I will set a higher ISO, the smallest f/stop on my lens, and a shutter speed I can hand hold, and go from there. Some times I open up a bit, sometimes I lower the ISO. This light plays havoc with the metering system. On aperture priority, the camera tries to make the scene too bright. You could dial in some -EV, but I find manual works better.