For a gentleman of your size I would recommend a single-breasted jacket as it does tend to make one look a little slimmer.

想你这种身材的绅士，我推荐双排扣的上衣，因为它可以使人看起来更苗条一点。让我帮你量一下尺寸。

youdao

Formal day-to-day wear includes a black single-breasted jacket and waistcoat, gray pinstriped trousers (pants), which shirt and gray or black tie.

正式的日常服装包括一件黑色的单排扣上衣和马甲、深色细条纹布长裤，配上衬衣和深色或黑色的领带。

youdao

Initial appeals have revealed a grey single-breasted jacket the man was wearing was made in Chesterfield.

BBC: JW Marples jacket may be mystery Newbury body clue