"High altitute" shot of milkyway - quick advice needed

Got the opportunity tomorrow to spend the night at 3100m

If the weather and moon cooperates I'm hoping to have a few night shoots (new experience)

I'm thinking to use a wide angle (10-20mm) to get a milkyway shot.

What shutter speeds can I use - this will be fairly cold (-20C) so no time for 3 hours experiments !!!

With the 10mm I should be ok upto 1min in exposures ?

• I do not have any tracking and would like to get some mountain tops in to give a sense of location/scale. (have tripod though)

Is there any idea in using stacking of multiple exposures - never tried that but guess this would be the use for it ? How many should I target ?

So in short recommend shutterspeeds ?
No of exposures to stack ?
Any other advice is welcome

Thanks
Jens