I generally used long scale since there is more selection. But you have to make sure that the string will fit in the tuner. For flats, I tended to go down a gauge. For example, I would use 100 chromes rather than 105.
If you have an old set of strings that you want to try... the best thing is to try it with those before you spend money
I don't know that bass, make sure it is short scale and not medium scale. Short scale is basically 30" and medium 32".