I am contemplating an eight week visit to Kunming from mid-October to mid-December to see if it's a nice enough place to live for an extended period next year. I have a masters degree in Chinese and several years experience as an English teacher. Is it easy enough to find temporary part-time teaching work paying around RMB125 a class?
Any leads/offers?

I'd say 125 is a bit steep. Maybe you can get a few students if you get recommended by people set up in Kunming already but 100 yuan is usually what they'll pay if you're any good.