Right now, I'm using D'Addarios - solo A, orchestra D, solo F#, and hybrid B...more or less what Quarrington recommends on his website but a different brand sting. I like this combination except for the A string. It sounds fine pizz and with the bow, but it's a little thin and lower tension than I'm used to. I don't have any experience with solo tuning strings except for the above though, so I don't know if this is normal for solo A strings. Of course though, with 5ths tuning there is a wider range of pitch to cover and so I expected that the strings would feel different than EADG strings...especially for B/C strings. Anyway, what are you using for 5ths tuning right now? Are you using the dominant brand or the Red Mitchell set or what?