I used to have the Lumix 7-14 and I didn't like it at all. No filter threads and the focus by wire are huge deal breakers. I sold it and bought the 11-16 and this adaptor: http://www.amazon.com/RAINBOWIMAGING-cameras-adapter-aperture-Panasonic/dp/B003TROEBM/ref=sr_1_2?ie=UTF8&qid=1366218324&sr=8-2&keywords=nikon+g+to+m43
I like the lens SO much better than the 7-14, and the adaptor fits perfectly fine, and the aperture control is nicely dampened. If I were you I would definitely go with the Tokina. Or if you have the money also look into the olympus 12mm f2.