Nanawind, if you decide to buy any shapewear, have a practice run at home, one thing I found useful was an all day panty liner, because they get quite sweaty.
What I also found useful was spare underwear, because after wearing them for 3 hours at a wedding, I couldn’t wait to take them off!
Hot, sweaty and uncomfortable, not only that but every time I touched somebody we both got a static shock, probably due in part to the carpeting in the venue, but, never again.
Apart from a close friend noticing that I had lost weight ,all eyes were on the bride and I just felt uncomfortable.