We deal with this further north much more than you may and it is an issue. Right now with tight inventories, I'm showing homes in the dark more often than in the past. If a new listing appears on Monday or Tuesday there is a real chance it will be sold by Saturday.
Starting in the dark doesn't mean that the final decision will only come from that one showing. If a home looks very good upon the first showing, I've had buyer's schedule a break from work to come out the next day to see it again in the daylight.
We do what we can given the conditions we have. Right now we are dark by 4:30-5:00 but come summer we'll be light until almost 10:00.
When showing homes in the dark, you miss so much...you miss being able to see the surrounding neighborhood. the way the light falls in each room, the backyard, and much more. I certainly try to show at another time although I have done 'dark' showings a few times in my career.