A lot depends on what you will be doing.
Figure 8 slalom = larger fins
Downwind slalom = smaller fins
Free sailing = ?
I have the '08 111 and didn't like the 38 and 44 fins that came with the board. Fast but bad spin out, so I bought a Tetonics Tomcat 42. I mostly free sail and am very happy with the Tomcat for my 6.6, 7.6 & 8.3. NO spinout. I weigh 79 kg. I could use another smaller fin for the 6.6 sail, but haven't invested in one yet. I also use Maui Sails TR-4's
I don't know if they have re-designed the Drake fins for the '09 boards or not. Very few reports of anyone liking the Drake fins.
At 105 kg, you can use some pretty big fins on the 111 (40 - 48cm).