Thanks guys
Sorry it took a bit to post on this didn't see it until now.
I would defer to someone like Scottwax to answer your question npjohnson.
As for the working time on that particular scratch... it probably took five minutes or so on that panel.
I personally would get (and did get) the OP and OC just becuase after much advice here I always try to go with the least aggressive product first.
So I would (and did) start with OP and on other cars I've done the OP with an orange pad worked fine and I didn't need to use the OC.