Regarding quantity, I'd say at least 2, if you plan to work out in them as well. If you get a bra that you have to put on the loosest hooking, as you lose weight (or the band relaxes) you can just move the hooks in tighter.
I have found that Kohl's has a good selection of larger cup sizes, at least when there's still a "D" in the cup. I have this bra here, in a 38DD, and it is the most comfortable bra I have ever owned. When I get down to my goal weight, I anticipate being a 32 or 34 band, and either a DD or DDD, like I was before I gained weight. I've worn nothing but Vanity Fair bras since I hit a D, which was around age 15, so they've not failed me yet in almost 10 years. And they're very reasonably priced!
Fair warning.... there are 4 hooks, so you'll be locked up tighter than Fort Knox, but it's super comfortable!
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