True, i guess i would have to test that out. But as i said, my hands are BIG. I was worried about them cramping being i would have ZERO wrist rest area I'm used to. Even my bottom of my palms land on the wrist rest area on my 13" MBPR instead of my wrists. I actually enjoy plugging my up to a external and using a FULL SIZE keyboard A lot of times. I watch a lot of TV in my room with the big 65" on the wall, and honestly i always either have my iPhone 6 plus with me, or the 13" MBPR. To me the MBPR feels light. When i felt the MBR the first time i was like OK, this is STUPID lightlol.
But i get what you are saying. Thats why i stay out of the Apple store, so i can already trick myself into thinking what i have is light lol!
If your hands are that big and you're used to using a 65" TV, the 6 Plus, etc. and the 13" rMBP feels light to you...then of course you should stay away from the rMB.