How much lead?

[DaveBarber]

I can tread water without kicking with both arms above my head.

My BMI is 24!

[steelemonkey]

And don't forget that the whippets will need correspondingly less neoprene to go round themselves.

OK Jen, now I cannot free my mind of a dog in a wetsuit. Thanks.

[Tim Digger]

OK a bit of physiology/anatomy! The human lung is the most buoyant bit of the human body. During exercise one breathes deeply and at the top of lung volume, until learning how to breathe best for that activity. Breathing in and out occurs at a variable place in your total lung volume, the further up the lung volume the more air there is in the lungs and the more buoyant you are, the more you struggle to get down the fuller your lungs become as you fight to submerge.
There are issues with new suits but trying to overcome them is often self defeating. Take the lead you need but be prepared to shed it quickly.
Best of all Relax