Wow! Thanks a lot for sharing your settings.. .
Though, I used a point light as the key light for general illumination and spot lights for the bulbs. I used D.Map shadows because ray tracing was taking too long to render. I used adaptive sampling with sampling quality 2. And I got that. I didn't use area lights because I didn't need light rays from outside.

PS: I tried quadratic and cubic it wasn't even displaying anything. However, only linear seems to work fine for some reason so I chose it.