I had 4 hours on the PA28 when I got carb ice in 75% power cruise. At 1000 AGL. At night. (This happened just 2 nights ago.)
I had carb icing on my very first flight in a 28! It's the only time I've ever had it in any aircraft as far as I know.
To the OP, I would say one flight with general handling and a few circuits chucked in at the end will do it. The biggest difference IMO is the view, you can actually see where you are going when you turn. Quite novel at first.