@Maro2bear:
There is definitely nothing wrong with exposing them to light. The presence of light is never a bad thing, even if the plants are dormant.
People get into trouble when they put their plants in a warm, dark environment. They use up energy to produce leaves, but no photosynthesis occurs to replenish this, thus slowly starving the plant. For a cutting, this is OK initially, but once the leaves and roots start to form, it's important to give them some light so they start to rebuild energy reserves.
I don't have any experience with temperature fluctuations day vs night. I would think that as long as the nighttime temperatures are above a certain threshold (let's say 60 degrees), you will be fine, but that's just a guess. If your cuttings are exposed to nighttime temps in the 40s and 50s that might significantly slow down the rooting process, but probably wouldn't kill it outright.