I also use Nikon FF and Fuji. I recently travelled to Arizona with my usual D810 camera bag (Think Tank Retrospective 20), the 24-70 and a 85 1.8. My X-T1, 35 1.4 and 16 fit in no problem after I removed the 70-200. Along with this as the carry on, I also had a x100S in another small "personal" bag. While there, I mostly used the x100S while walking around and the D810 for the Grand Canyon. It just worked out that way on this short trip.
For most purposes closer to home, I mostly use the X-T1 with the 16 1.4, the 35 1.4 and recently acquired 56 1.2, along with the x100S. Although I often use zooms on my Nikon, I value the more compactness of the Fuji primes and don't find it an issue to change the lenses when necessary. The quality of shots on the Fuji with primes compare very favorably with those from the D810 with the 24-70.