a p.s.: I know very little about Nikon's and their performance so I can't give you any information about them. I wanted to add that you wrote the scope is lightweight. My Canon, with the 300mm lens attached would do best taking photos at the 300mm on a tripod. When Spring does get here and I go on hikes and such, I also have a backpack to hold the camera, lenses, battery and will also attach the tripod for hikes. If weight is an issue (don't know how or where you'll be using it) the camera can require additional items and therefore, weight.
I do know that there are folks who use point and shoot cameras (much less expsensive and much more lightweight) with 8-10 megapixels along with digiscopes to take photos. Other than knowing of this practice, I can't say how it's done or give you a direction to look into it.
Again, hope this helps. Best, Emily