I'd have to agree with Bob.
For the first few years of owning an Airstream, I used Walberinze Super Seal exclusively. I found that after a month, maybe close to two, the beading would diminish. Walbernize does not last very long.
I've been using a good car wash fluid and a good car wax with carnuba in it since year 3 or 4 of ownership. I found that this lasts nearly 4x as long. Given that it takes me a full day to wash and wax, doing it once in 4-5 months compared to every 1-2, to me was a more efficient use of my time.