ArmoredDiver:
So here's a follow on question, I am just stepping into a BP/W setup myself and I am looking for suggestions for wings. I'm planning to dive double steel LP 95's and using either one or two stage/deco bottles as needed by the dive. What sort of lift should I be looking for?
Tanks play a part in wing selection, but so does the buoyancy of your exposure suit.
You cannot size a wing without knowing the initial buoyancy of your exposure suit.
You need to start the dive negative by weight of your gas. ~200 cuft of air or nitrox will be about 16 lbs. Just to stay at the surface you will need to use some of the capacity of the wing.
Lets say your drysuit makes you 22 lbs positive if you are wearing just the undies and the suit and have vented all the air you can from the suit, at the surface. That means you need another 22 lbs of ballast in addition to the 16 you need to offset the weight of your gas. What happens if your suit fails and cannot trap any gas? You stand to loose 22 lbs of buoyancy.
Do you want to be able to add a little gas to your suit at your shallow stops for warmth? May 2-3 lbs.
If your suit is really 22 positive you would need at a minimum about 16 + 22 + 3 = 41 lbs of lift. This is also the total amount of ballast you need.
Assuming you are using faber 95's your tanks are about -3 lbs empty , 19 lbs full. A plate and harness is about -6, bands and manifold, about -5, regs, -5, can light -2
With full tanks your rig will be about - 37 lbs with full tanks, and about -21 with empty tanks. You will need about 20 more lbs of ballast in addition to your rig.
The minimum wing lift you need, based on the above assumptions is about 42 lbs.
Your stages, because they are ditchable should not change this. Remember you have used about 19 lbs (16+3) of your wings capacity just to stay at the surface, that leaves another ~23 lbs available to offset the weight of a stage. A rigged al 80 full is only about -4 lbs. If you were to suffer a suit flood, just drop the stage bottles.
Hope this helps. Get some real suit buoyancy numbers before you shop for a wing.
Tobin