Received the following reply from Galco about the fit of their VHS which is listed as fitting the Model 686 4":

Thank you for contacting Galco. Unfortunately, the VHS4.0 shoulder holster is not made for the S&W L frame model 69 in 4.25” length. The ¼” longer barrel of the S&W L frame model 69 is not recommended fit for the V4-104 VHS holster. A custom option is not available.

Will study the Bianchi more closely and maybe what is needed is a longer retaining strap.