A three piece is very complimentary to you. This fit is instructive on how a three piece, when properly fitted, brings all attention to the face and creates a solid impression of the body, elongates the body, without the body being the focus. This is a series of strong "v"s: jacket button point, vest top button point, and strong shoulders. When the jacket is unbuttoned, the top button point on the vest continues the job of drawing the eye to the tie, collar and face, with less interruption and pause if the vest were not present.
Jacket buttons at narrowest part of the waist, and vest just above sternum for slimming effect.
Very nice quarters on the jacket create a nice figure eight (like Claghorn's grey suit posted earlier today). Besom pockets are the right thing here as well.
That looks like some very heavy cloth. 10+ oz?
Yes, cloth is a heavy flanell cloth