The charts are pretty helpful. The suit should be tight but not restrictive of breathing. You probably need to wear it for 10 minutes if it is initially uncomfortable. If it’s a relief to take it off, then you might want to consider other options such as a 2 piece mix and match off sizes. If you haven’t had a lot of experience with restrictive spandex, I’ll just say that you can squeeze into some really tight stuff. So you should use breathing and comfort as your guide. It should be tight…just not too tight…if that makes any sense.
Gunnergirl:
I just got off the phone with 2XU to confirm their sizing. On the tights at least, it is based on waist size and inseam length, so weight is somewhat irrelevant. The tight should be long enough to cover your achilles and obviously they should not be too constricting around you waist. Here’s 2XU’s recommended sizing:
XS = 27-29" waist, 67-74cm inseam
SM = 29-31" waist, 75-79cm inseam
M = 32-34" waist, 80-86cm inseam
L = 34-37" waist, 87-94cm inseam
XL = 37-40" waist, 95-102cm inseam
XXL = 40-44" waist, 103-112cm inseam
I hope this helps.