Figuring out weight differences for a different suit?

[Spectre]

Do people have any suggestions for calculating weight belt changes for a new suit? I currently dive with a 2 piece 7mm suit, and I'm getting a 1 piece 3mm suit for a trip. I'd prefer to not be screwing around with my weight belt trying to figure out how much I'll need with the new suit.

The only thought I had was throw my suit in a gear bag and hang weights on it until it gets neutral, then doing the same with the new suit to figure out the bouyancy difference between the two, but unfortunately that might be a pain in the cold water up here!

 

[WreckWriter]

I'm guessing without knowing your size, diving comfort, weight worn with the 7mm, etc but I'd say you'll be quite heavy with half your 7mm weight. If it were me I'd start with 1/4 of the 7mm weight.

Tom