soaking eventually ruins the harps and lessens their lifespan.
If you are really into bending I recommend Honer Golden Melody: they bend and over-blow easily The only problem is the curved edges make racks difficult
If you are really serious, check out the Joe Fislisko custom harps.
He has a diverse set of customers ranging from Howard Levy to John Hammond Jr.
http://customharmonicas.com/joe-filisko/