My advice is going to be even more simple and generic.

i'd say, you should really get fitted and have a corset custom made for you. Yes, it looks scary and can be quite expensive and troublesome and it takes ages, but the benefit is having a corset that actually fits you and is well made enough to last more than one wear. Unless you lose weight dramatically, well made and well fitting corsets last for years!

There's lots of troubles with off the rack corsets- busks can be cheap and break straightaway, people skimp on boning or don't use the right material so the bones end up pushing straight through the corset, they're too long so you can't sit, bla bla bla. There's lots of issues. That, and every body is different- you might need more waist reduction and little to no breast/back/hips reduction, or you might want more pressure on all of those areas.

Also, it depends on what type of corset you want, how often you'll be wearing it, and what for. There's lots of variables. Your best bet is a custom fit.