At the beginning of this forum is a Sticky on Lift Calculations.
http://www.scubaboard.com/forums/bu...ems/158370-ultimate-wing-lift-calculator.html
I don't know how to link to this in the message.
However the first poster has a link to some excel spreadsheets that will help you do the math taking into account everything.
Here in the US we definitely have the mentality that bigger is better. Not very one likes the BP/W combo so they make BCD's that have a lot of lift. Is it necessary? Maybe, maybe not.
Years ago I started in a DR SS Transplate with a Rec wing. It had something like 50+#'s of lift.
Quickly I ditched the harness system it came with and went with a simple one piece harness.
For a couple of hundred dives I felt like my buoyancy was never perfect. I felt like I was always being rolled to one side or the other and I was always having to scull with one foot or the other to level myself out.
One day I grabbed by buddies set up. Nearly the same except he had a 30# wing on it. My buoyancy was spot on. I could lie there motionless. I think the tank I had on was the HP117 steel tank.
Air consumption also improved.
Now I have a 30# travel wing for singles and a 60# classic wing for my doubles.
Look at what tank you likely going to be diving and its buoyancy characteristics, and a couple of pounds for a light, so on so forth. Once you do the math, you may find that 30#'s is a lot.
Since you're doing a BP/W combo you're likely going to have a D-ring on your butt. This is a great spot to attach a dive reel and lift bag. A lift bag where you can manually dump the air acts like a redundant BC.
Also remember that a proper weight check will also show you that your wing is, I don't want to say irrelevant, but isn't as crucial until you start diving doubles and stage bottles. When you tank is low (500psi) you should be able to have a completely empty BC and bob at eye level purely by holding your breath. If you can do that, you're just about perfectly weighted.