Jerruh!

Couple things. I never shill my own stuff, hell I haven't written anything on the site in a while, but here's a link (we're allowed to do this right?) to a review I wrote about CM business class. My Review

Now, if you have expert flyer or anything, you can check and see how many business class seats are sold. I've always bid the lowest amount possible on these, usually successfully.

Bid whatever you're comfortable with. I will say though, CM often has plenty of empty seats in my experience, in J or Y. So if you don't wanna spend any more money, there's a good chance you can probably get yourself a row solo towards the back.

I can't say for sure how Copa processes these, but you'll often see J cabin is full on CM, so it leads me to believe anyone that makes even the minimum offer will be accepted as long as there's seats available.