With a 5 you need to watch muting and a pick player may have a harder time with this. Most 5ers seem to be finger players.
If you're band in Eb, playing a standard tuned 5 will be confusing. Tuning it down a half or full step will really take the useful tones out of the B string. Drop tune a 4 (and get and octave instead IMO.)
In a studio I would record many parts with a 4 and overdub with the 5 some low notes.
35" and String through bodies shine here. (Playing a 35" also makes playing a 34" fretless easier. Stretch is there in muscle memory)
With A Five you can get Short Scale fattness out of the upper region of the Low B.
You'll be able to use it as a consistent thumb rest and greatly improve right hand mobility
You'll need more out of you're amp in wattage and EQ
If you plan on bouncing back and forth between 4s and 5s, expect confusion. If not good for you. I got it and have kicked it. But be prepared to practice and if you gig, know which axe=tune.
An upright technique i know not the name of, if any requires a 5... for a great thumpy tone, rather than striking the string you pull it like a bow and arrow i suppose and when it releases you get a thump as you're finger or thumb hits the adjacent string with the energy. Release the E to thump into the muted B. No B No thump.
We spend allot of "Working" time in the first five frets. A 5 really does add allot of useful low notes where we need them and a second position to get them.
I still play a "4" when I use the 5, meaning I ignore the 5th string consciously when writing or learning parts. When I need it tends to be:
Ghost, octave and "thump" notes
I used the low D allot. C# C some. B open and proud only 2 times night (BOOOM)
It has the possibility of eliminating big jumps on the neck and simplifying difficult passages.
Songs in Eb, D, C# get a nice Low note.
Fat short scale tone on low strings, higher register.
Hope this Helps. Lakland 55-02 AWESOME 5. Lakland Jazz 5's are great too.