I suspect that given the cost and behaviour of the LCD shutter that you are probably better off using the DSLR in video mode. In that case you can get a direct measurement of angular velocity and time from the video stream. I have done analysis of DSLR stills for various events using Astrometrica and it is hard work to get anything really useful from the images. With video it is much easier to extract the path and angular velocity and also much easier to eliminate other things like glinting satellites. This image is a stack from 1/25s video frames. The small gaps in the trail correspond to the very short dead time between exposures of the sensor. I’ve posted some of the individual frames here.