Mobil 1 is a good choice, and anything synthetic designed for high loads is what to use. I use Finish Line Bicycle Chain Synthetic Oil (black bottle, green top) which is slightly cheaper and still lasts for ages!!
One drop is all you need for a couple of meetings, and then clean out with motor spray, or lighter fluid, before the next oil. Don't put oil on oil, as it builds up and then attracts dust and dirt. HTH