My rule of thumb is: if I was feeling cold last time, wear more insulation next time. Most of my friends in this chilly part of the world started with not enough insulation, and bought thicker undergarnments or undies.
The trade off is weight. It is rare to be too warm, unless the water is + 20°C. But more insulation needs more lead.
The trade off is weight. It is rare to be too warm, unless the water is + 20°C. But more insulation needs more lead.