A friend and I plan to observe and image the eclipse in 2017. We hope to set up the imaging sequence correctly and try to not only image the event for photographic interest but image some of the stars around the sun to test Eddington's Experiment of relativity. We should have a resolution of 1" per pixel or better but the exposures are what I an curious about.
Having never imaged a total eclipse I was wondering if anyone has insight to best time exposures and DSLR settings, photographic filters during totality if needed, I have white light solar filters for the before and after. I would like to record stars up to about 11 mag which shouldn't be that long of an exposure.
We will be in a location just to the side of the center line and have about 2:20 of time to image, probably about 2 mins just to be safe and have the filter off before totality ends.

I am already aware of many people's feeing this should be an event observed and leave the equipment alone but since I an a pretty experienced at AP, I think I could get the subs I need and observe the event at the same time.
Yes I have imaged the sun before and understand the safety of having the filter on the telescope at all times when the sun is not at totality.

Thanks for any input on the exposure settings

As of right now I have my Skywatcher 120 with my Canon T3i and a C8, .63 focal reducer, with my Canon XSi. I guess I can autoguide if needed.