"It turns out I have a Shimano FD-M610 which is a clamp-on. Interestingly, it's 3-ring capable but at this point I think I'm sticking with a bigger 2 ring. Specs say that it's max ring size is 42T (what I'm running right now) but you're saying I can just raise it and it'll be fine for a 48T?"

Bit of a crap shoot. Many FD's are shaped to specific chain ring sizes, with a cage shape that is matched to the curve of the largest chainring. Your's is likely matched to the 42 ring, but I've no clue with SRAM gear. When the FD shape doesn't well match the ring, or there's a huge difference in rings, you can't get the FD into a prime shifting position of 1-2mm. The bottom/rar of the cage may be close, but the upper section won't be. Thus index shifting can suffer. What most folks do is try it and if not, then change the FD to a model matched to the larger ring. FD's are cheap, relatively. .