A few words about sanding Micros.  They sand away nicely as long as they are completely cured.  My experience shows that after 24hours, it is dry to the touch and it is hard.  It is, however, not completely cured and if you try to sand it or file it, you are going to end up messing up your sand paper or file with clogged materials.  It is, however, a nice time to knife-trim.  It is not yet brittle and you can cut away in a controlled fashion. 

    After a week (I don't know exactly when this happens, though) the Micro is completely cured and brittle.  When sanding, they produce nice fine powder and does not clog the paper.  This, however, requires some protection when working on it.  The resulting powder is very light and gets easily airborne.  Use some sort of breathing protection.  Also, it's not hard to imagine this stuff will do a number on your eyes as well.

     Here you see the results.  Nicely smooth rudder transition.  Done on both sides.  I hand sanded this part without the aid of power tools since I was concerned about taking too much away.  Micro is soft and it's very easy to take too much material.  You can always fill it with more Micro but it's a pain.