Thankfully for me, I don't have to actually go out and upsize my wordrobe - at least, not by much. I dropped 4 1/2" since February, so a lot of my shirts and pants how fit me more than loosely enough for the task.
I've been going at least one size up, regardless. I've never been a fan of having my clothes fit even remotely tight, so this is sort of my standard style of wardrobe, anyhow. So, I might normally wear an LG in shirts/t-shirts, but size up to a 2X for CC - I'd prolly just go w/an XL if I weren't now CCing. I was already wearing 2X, so the majority of my existing wardrobe is perfect.