I would just add that the more ripe the bud is, like if it is producing flowers already, the less time generally before you can cut--harvest--the plants. (I am assuming that you are concerned here about plants that are stalk cut, though I know that you do have flue cured--it probably holds for both primed and cut types)
In Connecticut, the broadleaf is cut about 2 weeks after topping. However, if you top early, shortly after the buds appear, the plants can remain up to 6 weeks or even longer before cutting.
I live in a similar climate as you, on outer Cape Cod in Massachusetts, close to the North Atlantic, a thin peninsula 40 miles out to sea. Nights are already in the 40sF and a high of 70F is as good as it gets. It is humid most days, which is good for the tobacco. We've been lucky with a lot of sunny days but usually this season is damp and cloudy.
I topped my plants as soon as I could for 2 reasons. One is that I started late, and the other is that I am anxious to grow the biggest and ripest leaves that I can before I have to cut them. I hope for good weather into October with no hurricanes or Nor'easters but that would be unusual.
Hope that is a bit of a help. Generally, if you are growing in a region with a colder climate and a shorter growing season than in the usual tobacco growing regions, I'd think it wise to top early as soon as the buds appear and not wait for flowering to occur.
CT