Hi juniper - I have a major “thing” for VB jackets. I’ve managed to acquire 7 (blazers are my thing) and have 6 dickeys. I will tell you the VB makes incredibly well made and flattering jackets. I’ve been fortunate to score all but one (my beloved scuba - because it almost never gets reduced) on sale. I do think size varies by cut. Although most of my jackets are size 4 in VB, two of them are size 8. The miller style runs big as does most double breasted. I have the 4, I could have taken a 2. The long and lean runs small. I would need a size 8. The lonny and scuba run TTS I have the 4. The Matteo is TTS but slim. If you are between sizes size up. If the material had stretch go TTS. If no give, thick material and a narrow non double breasted cut consider sizing up unless you like your jackets snug. For reference I am 5’3” 111 lb. usually size 4. In designer theory 8, helmut Lang 6, Iro size 8, Smythe 8, Rebecca Minkoff 4-6. Hope that helps.