Handy thread!

I've tried searching but cannot find a list of fare classes and restrictions. My wife got the $200 statement credit offer for application of a DL Gold Amex a couple of months back when buying a DL flight. The application crapped out on the Delta website and we ended up putting it on another account. I'm looking at buying the cheapest fully refundable fare I can in order to trigger the credit but can't tell if what I'm getting allows that.

I looked up refundable options for JFK-BOS and it's listed as an H fare for $279. Is that going get a full refund of the total ticket price? I know typically Y, B, H are the most flexible economy ticket options but didn't know if I should be searching out Y specifically. Is cancelling tickets on DL for refundable fares easily done online?

Whilst I'm at it, anyone know any cheapie routes I should look for on the refundable side? Not a big deal but if I can float less cash for a few months that'd obviously be preferable.

Thanks in advance!