[sakuralovebot]

Currently having to judge between the strength of two metal-ligand interactions:
Co3+ --- OH– and Co2+ --- SH–. I know that metals with a higher positive charge make better Lewis acids, so I feel like it might be the OH complex. However, OH- is a stronger lewis base than SH- is, and strong acids interact better with weaker bases, right?

Google + textbook is not helping. Any advice would be appreciated.

[Borek]

Broadly speaking the only sure way is to compare complex stability constants. While crystal field theory and/or ligand field theory give some hints in the end you always need experimental confirmation.

In some cases CFT and LFT give more or less unambiguous answers, no idea if that's one of them, haven't used them for way too long