What I'm thinking of doing for this shoot is scrubbing the one long exposure and instead taking about 90 minutes worth of 30 second exposures and then stacking them in a free Startrails program I downloaded. This will ensure that if something goes wrong at some point (dead battery etc.)during the shoot, I will at least have however many exposures I have taken up until that point. I will leave on the Long Exposure Noise reduction so each 30 second exposure should take about a minute for both exposure and noise reduction to process.
It also means if I need to leave after an hour, I will at least have an hours worth of exposures complete
Does anyone have any input as to other advantages or disadvantages to stacking multiple exposures as opposed to one long exposure. One thing I will have to test is how well the mountains in the foreground will be exposed with only 30 second exposures, as I want them to be a feature. I don't think my flashlight is powerful enough to light them