New tank and wing

A few weeks ago I got a Transplate and love it. I have the steel plate, STA and Travel wing. Im NEVER looking back! With an Al80 I dont need any weight in fresh water. Im a big guy @ 280 lbs and 6' 3". This weekend with a 3 mil farmer lower I needed just 6 LBS. Now I want to get a tank. Im thinking about a HP Steel 120,130 or 149. What size wing would I need for fresh water? My biggest concern for now is when we go to the Caymans this summer and I have a 100HP steel on. Will the 25 lbs wing I have work or do I need something bigger? A secondary concern is my wife has losts of trouble with buoyancy and I might need to help lift her. So I would like a little extra lift but dont want a 85lbs wing that tacos around a single!


Later Mon,
Nick

First off I don't think you should even need to lift your wife whether she's having buoyancy issues or not.
If she needs to inflate her BC then inflate it for her. Grabbing a hold of her and trying to keep her lofted off your BC is asking for trouble. You'll be putting a lot of input in your BC every time you grab a hold of her and every time you let go of her.

As to your tank question, HP 100 tanks can be around -9lbs bouyant when full. Do the math of all your other bouyant weight (both + and -) and see if the net sum is above -25lbs, which is the max amount of lift your wing an compensate.

Look at the bouyancy of your lead, ratio between your usual tank and the HP 100, regs, giant knives, camera equipment, exposure protection etc etc.
Tank Spec Chart:
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan