I remember there could be as much variation between individual Super Vampers as between vampers and blues harps. Some were much better than others.

Yes, the wood did swell up when you soaked, then after you sanded it down, it could shrink back too far! Sometimes bits broke off the comb, too. I still think it must have been the seal that made the difference, because I can't believe that water would affect the metal reeds, and it doesn't seem to make a difference with the plastic ones.

After soaking, you seemed to need less breath to produce the sound, especially when bending.

Perhaps I will try a Lee Oskar next time I buy one.