The pups sure look wide enough to cover the B string well and a neck-thru construction shouldn't cause issues either. Perhaps the factory B string has a cheap quality and went dead early (as B strings tend to do in any case). When my dealer has them, I'll give the 5-stringer a try. No Gibson 5-stringer I own has issues with the B string, but the Epi Non-Rev TBird did until I changed the pups. But that was a model from 15 years ago, they should have learned from the past hopefully ... If the B string doesn't sound right, then the Pro V is not going to be around for very long.