I turned my heatsink up today at work for my 100mw red Module. I made it out of 2" Ally bar and added some fins along the length to give a greater surface area for heat Dissipation. It is not a transition or press fit but rather a "snug" fit, so I can remove the diode without damaging it. It seems to work really well, I did a 2 hour test run and removed the diode. It wasn't even warm 
Here is a picture or 2
Jase.

Here is a picture or 2
Jase.