I used to tune C standard....so C, F, Bb, Eb
I used high tension Newtone custom strings (around same price as Elites/DR's etc)
I told them my tuning, and my preferred guage (which was 45-105) and they made them for me!
Simples
Had similar tension to that of a standard tuned bass, with a similar action.
Its all about tension (core size), not guage!
Try Newtone Strings
Si
p.s.
I have no affiliation, I just think they're spot on!