Of course it could also mean that she could be stronger than Priscilla and still have #10 but I think it's safe to assume that usually they're not #1 material and they're not good fighters (since all they do is polishing their special skill and staying at HQ at all times, preventing them from gaining experience). So if I were to choose solely on their potential I would say that Clarice would have better chances of winning. However, in this case, at this point, I think that Clarice would panic and become another victim of mind f**ker. But that's just guessing, for now we know too little to say how it would work out. We haven't seen either of them show what they're really made of.
"For generations, the organization's #10 is chosen without regard to their true strength, to be a warrior that excels at a certain particular ability..."