OK, that makes sense. Because most red dot sights work fine at night; they do essentially the same thing as a laser. But if your red dot doesn't work at night then it makes sense to use something else. Though I'd caution against using two different sighting systems depending on how much ambient light there is.
The key to a good HD gun is simplicity. I already don't like anything you need to turn on (the Aimpoint PRO on my HD rifle is always on); that just adds one or two precious seconds if you need to defend your home quickly. And if you're flustered enough, that can easily turn into even more than just a few seconds if you fumble with the switch.
But having two different sights and needing to decide which one to turn on adds a whole other level of complexity. It's yet another thing to think about when you're grabbing your rifle to defend your family: Do you really want to have to think about whether to turn on the red dot or the laser? What if it's dusk? These decisions seem easy right now, but in the heat of the moment it's just going to add to your stress and potentially slow down your response.
Then comes the shooting aspect; you're going to be shooting your gun using two different techniques: With the red dot you're looking through the sight and seeing a reticle, and with the laser you're looking at the target and seeing a dot.
Your setup seems needlessly complicated for HD use. I highly recommend just going with one sighting system for your rifle, whether it's a laser you use during both the day and night, or a better red dot that works for the night time also.
