For a wing that is Lighter Than Air, I think you can use the same analysis you would use for a Heavier Than Air glider. For a glider in equilibrium, a simple force-balance diagram can be used to show that the flight path angle is the inverse tangent of D/L. This result gives you roughly "10 feet forward for every foot down" in the case of a glider with a 10:1 L/D. The same analysis applies to a Lighter Than Air wing, you just need to put a mirror at the top of your diagram and look at it upside down. This will show that if you have a 10:1 L/D, then (in equilibrium) you will move 10 feet forward for every foot you move UP. In other words it tells you what your MINIMUM sustained climb angle will be. All steeper climb angles will be available to you.

At first glance, it is a bit curious that the glide ratio for a Heavier Than Air glider doesn't depend on weight. For the same reason, the minimum climb angle for your wing will not depend on how buoyant it is. However, if you start to pull on it with control lines, then the all bets are off, and the simple force-balance diagram is no longer simple. I'm not sure if this helps answer your question or not.