i am another fan of contrast. when i was fit and thin, i loved feeding my partners and seeing them grow soft. my last partner at a fit man was a ssbbw who was almost 3-times my size when we met - that contrast was amazing!
now as a fat guy, i am enjoying contrast from the other side - i am more than twice the size of my current partner.
being the "bigger one" in a pairing wasn't ever a goal or desire of mine, but i will say that when it happened i've really grown (pun intended) to love it.