Everybody is different in terms of how they perceive recoil and how it affects their controllability for follow-up shots. For instance, I've tried Buffalo Bore .38 Special +P 158gr LSWCHP in my 642. After 5 rounds I realized I would never try that again! However, there are people who carry this load in a lightweight snub and are confident in their abilities to deliver accurate fire quickly. I think the only way you're going to figure it out is to try different types of ammo for yourself to see what works. I do think starting with standard pressure loads before going to more powerful +P loads is a prudent method for evaluating ammo. I can't help you with the Hornady or Corbon ammo as I don't have any experience with them. However, I have heard good things about Hornady's loadings.

Personally, I carry 125gr Federal Nyclads in my 642. They kick about the same as typical 130gr FMJ practice loads, so I can carry the Nyclads while practicing with the FMJ. Speer's .38 Special +P 135gr Short-Barrel GDHP has some kick, and isn't too difficult to control when fired from my 642, but I was noticeably slower on follow-up shots than when firing Nyclads. For me, the Nyclads work as a primary carry round, while I carry the SBGDHP in strips for reloads. I like that they both have pretty good track records in stopping violent attacks.

I'd also recommend investing in some snap caps or dummy rounds and do A LOT of dry fire practice with your snub. The CT grips should be very beneficial in terms of skill development.

ETA: The single most important thing in terms of ammo selection, after reliability, is your ability to get good, consistent hits quickly. Anything after that is just icing on the cake, imo.