I'm trying to take an image during dusk before things like street lights come on, delibrately under-exposed to lay some detail into the film, and then i'm waiting for all the lighting to come on, and taking a second exposure to correctly expose for these lights.

In spite of ensuring that I tap the dark slides to ensure the film doesn't settle between shots (maybe 1 hr), I always seem to end up with a small mis-alignment of the 2 shots.

I assume this occurs when I re-cock the shutter, no matter how careful I am.

Has anyone any tips which may help me get the 2 images properly aligned?

Regards