It's been almost 6 months since we got the kit and we have only been working weekends.  At this point, we have completed a Rudder, all SLATS for the wings, the skeleton of the Elevator and Stabilizer, and almost 1 complete wing half.  We made a mistake while skinning the elevator.  Dad measured one side of the skin and I measured the other.  AFTER we drilled all the holes and cleco'ed it all together, one side was right on and the other was 3/4" over!  The skin ended up being too small and we had to order a new one. :(  Lesson learned: when working together, check each others work and make sure you are both measuring from the same place and understand the plans to say the same thing!