125cc - 140cc Motiva Ergonomix UTM Implants

My surgery is booked for 25th March! Feeling so nervous and every other day I regret booking in (but paid my £500 deposit so no going back now). I want SUPER subtle results - I'm starting with essentially nothing and hoping to be a full A / small B. I don't really want it to be noticeable to anyone other than myself. I just want to be able to fill out tops, feel good in a bikini, have something going on there! Torn between 125cc and 140cc - my surgeon and I have currently agreed on 125cc but I'm thinking I might be more convinced by 140cc especially as I'm a tall girlie (5'8).