Are you really going to make 40x60 prints and hang them where people can put their noses against them? If not, you don't need the Sony. (Although your Fujis would actually do quite well in such a test.) I gave up obsessing about super-large files when I learned that my Olympus E-M5 could create better image quality than my Pentax 6x7.
As a professional who has traveled to nearly 30 countries and around much of the U.S. on documentary assignments, I can tell you that equipment overload is a major photo-killer. One body with a mid-range zoom, another body for back-up, and a pair of primes of your choice, and you're set.
I carried my Pentax to India, Singapore, and South Korea in 1992, along with my Olympus OM kit of 24, 35, 85, and 180mm lenses. I got some great shots with the Pentax, but what a beast to lug around! I would have done much better without it. My Olympus 35mm slides made great 20x30s (one of which currently hangs in my living room). What more do you need?
As Picasso said:
“Forcing yourself to use restricted means is the sort of restraint that liberates invention. It obliges you to make a kind of progress that you can’t even imagine in advance.”
And Orson Welles concurs:
“The enemy of art is the absence of limitations.”