Tashigi was shown to be able to dodge a few of Monet's snowballs and despite Monet being in a heavily weakened state when defeated, I'd say it'd be pretty ridiculous to assume her power had dropped by multiple tiers. Coby deflecting a torpedo was impressive compared to his pre-timeskip self, but not a feat of physical strength that I'd say matches up to even the likes of Hatchan moving a giant rock and other low level Grand Line pirates' feats. I don't see them having the same rank as a means to compare them, considering the rank of Captain also belonged to bottom tier fodder like Morgan and Nezumi.
Coby's Kenbunshoku Haki may allow him to react to some of Tashigi's attacks, but I'd say she still stomps until we see more feats from Coby.