I have been practicing this combination on my robot. My take on this before you get real expert advice is to use the punch for a higher ball closer to the table against topspin and the topspin backhand for a lower ball when a bit more away from the table. The hiromoto type punch can be done off the bounce but it is a higher risk shot. It is a high risk very high reward shot. For a high backspin ball you need to get very low using legs and bend from the waist to topspin.
Answer for When to use backhand topspin and when backhand punch?
