Leupold scopes have smaller ocular and objective bells than the Nikons,
I have a Leupold FX1 Rimfire 4x28 on my FS with Warne QD mediums. It fits behind the rear sight and sits plenty low.
If you're going to be hunting, the leupold is plenty. Any target work at all, and you'll appreciate the extra power of the Nikon, and might want more.