So being a guitar player many years ago I always replaced a broken string with a new one of my favourite brand at the time . Poked the end of the string through the tuner and left the excess hanging in the wind as it were.
I’m in the process of tidying my old faux-Gibson SG bass and thinking about strings.
I have a set for 34” scale bass but the SG is only 30” so do I …
1/ Use the strings and cut off any excess
2/ Buy specific strings possibly flats for a short scale bass
Generally you want the strings to be short enough that they will taper before being wound on the tuner. Not mandatory as long as they fit on the tuner though.
I always cut mine off, too.
Thanks howard.
That’s another thing I can cross off the “ to buy” list as an urgency then. Trying to keep this rebuild to a minimal budget as I have my eye on a few other bits of kit 
I think you sould buy another set for the right scale because, if the string winding does not taper when it enters into the tuning peg hole, it will be folded and very fragile in this zone. that’s why the strings windings are tapered, by the way and as far as I know.
some folks do unwind a part of the string to shorten the effective scale lenght of a string but it looks a bit complicated.
and I always cut my strings too (either on my guitars, basses, ukulele and so on 
)
I agree, @terb . . . there’s a reason why they make string sets for short scale 
In the meantime, I think @Mac can get by with shortening the full scale strings as @howard said, and trying that out, since he’s experimenting anyway. 
Cheers, Joe
I hav no idea how to multi- reply so please excuse my lack of tech savvy 
Thanks for your answers .
That’s OK @Mac . . . we’re glad we could help
You can reply to any number of people in a post as long as you prefix their user name with the “@” sign. That way, they will see that they have a message or a post.
Cheers, Joe