only if and contraposition

Just a quick question: Do you think that any of the apparent counterexamples to modus tollens/contraposition would work if the conditional were stated using "only if" as the conditional marker?

1. If it rained, it didn't rain hard.
1a. It rained only if it didn't rain hard.

Try out any of the other apparent problems for MT/contraposition with only if in place.

The logically equivalent paraphrase in (1a) doesn't seem to have the same plausibility as (1), that is, I can't give a good context for using 1a.

I'm curious if any of you have thoughts about this phenomenon.

--Ian