I’m very new to night hunting. I just bought an AR15 in a 300 Hamr, and plan to use it for deer hunting, general use, and some night hunting. At first, I’ll just use a red spot, the Coyote Tactics unit, but later maybe a thermal scope.
Ninety percent of the time, I’ll use it in daylight with a traditional scope. How do you guys transition it for nighttime use?

Of course I can attach the red spot to my scope tube directly pretty quickly, or should I attach it instead to the rail?
And if I get a thermal scope, how do you transition from the normal scope to a thermal quickly, without having to zero each time? Or can you do that?

My Coyote Tactics is now attached to the scope of a bolt action, and it is pretty cumbersome.

Attach your light to the front rail, opposite shooting side. Put pressure pad on top rail where you grip. Easy peasy.

When you get a thermal, make sure you have QD mounts and check their zero reliability when removing and replacing. I have a SCAR that is my night rifle and i switch between a day optic and a thermal regularly. Zero holds just fine as long as I put it back in the same rail slot.

One challenge with NV is the narrow field of view at ranges under 25 yards. I either use a laser attached to the rifle or a pistol with a laser sight for walking up to larger hogs that I've shot. If there's room on the rifle, the mounted laser is easier as there's one less thing to carry. One challenge that I've found is that even a light AR gets pretty heavy and clumsy once you've mounted NV, a suppressor, an illuminator, and a laser.

QD mounts are the answer.

I use a LaRue one piece QD mount on my traditional scope and I use a ZRODelta QD mount on my thermal. I can flip them back and forth in moments and I've done extensive testing to validate they do return to zero being moved back and forth.

Good luck!