I play a 5 string and a 4 string. One thing to note is that the realtone cable itself can't detect a true bass low B cleanly - it can however detect almost all the notes below an open low B. 5 string songs can easily be done by changing the cdlc to rhythm/lead, for starters. Simply put a note on the song that this is a 5 string bass track, played in guitar mode. The other thing you can do is have the player tune up their B string to d or c which IS detectable. Then track it that way with a custom tuning. Often 5 string songs won't make use of all 5 strings, they just want the low B. Keep in mind that there are no notes that you can't make with a 4 string bass with a 5 string, just that they're several semitones or whole octaves below. Also, unless the song has open B riffs (or lots of notes on the g string) you can often get away with 4 string BEAD tuning - as most songs utilizing a 5 string don't touch the g string. Finally, I like to keep my 5 string tuned ADGCF so I feel your pain.