Here is my cooling setup on the TF360. It is a 'Pi-Fan' 5V fan which I had around. I have the fan blowing onto the CPU, and you need the fan staged off the CPU or the air cant get out, it will just fight with the air coming in. So I had some little rubber feet from PS/2 keyboards I butchered ages ago. I cut the feet and superglued them to the four corners of the fan, then superglued that to the CPU:
There looks to be lots of height on the CD32, but not as much as you want
Because of the lack of height if using a heatsink it would have to be very low profile, so a heatsink+fan looks difficult. I think you select one or the other. I went for active cooling.
Regarding my trick to stage the CPU off the socket if you want to remove to test CPUs was as follows:
Place the CPU onto the socket first and engage the pins, then slide the card in (slide folded end in first). I used just thin card used in packaging which was in my bin. I cut them 2mm wide and folded them over. I inserted them so the cut height was between the CPU and socket and not the thickness of the card. (I hope that makes sense).
To be honest I don't know how far the CPU would sit in, but I just wanted more of a gap to assist in the removing my CPUs when checking them. Once you have done it a few times you get a feel for the pressure etc.