I just got a set for my Dingwall 5 & wanted to try low F# ....
Really like the strings (except the F# .174 tho prob not the string's fault more the low freq) so I took it off & moved the others up & just added a (high) G .. so have normal low B (actually drop A in my case) ...
My initial impression is that I like these Circle K strings even more than the Dingwall or Payson but it looks like this low tuning set is the only one available in the UK that I know of (Bassdirect) I'd love to be able to just get the normal 5 string set next time I need a string change ...