Practice bass

What would be the correct strings to buy if I want to set up a concert uke as a bass to practice bass while traveling

If it's pure fingering practice you want, a set of low-G strings tuned GCFBb (ie raise the two treble strings a semi-tone) will give you the note-spacing you need to emulate an EADG-tuned bass ... if you actually want EADG tuning, sorry, can't help