Great project, but be careful with the panel's power rating. It is given for an incident light intensity of 1000W/m2, which is reached on a sunny day in central Europe around noon, with the panel facing the sun directly. As rule of thumby, a fixed panel installed at the optimal angle and direction gives the equivalent of 1000 full-intensity hours per year, a little bit less than 3 per day in average. It's more in summer, but less in winter, and depends strongly on the cloud conditions. So I guess your assumptions are a bit too optimistic.

To not sound that destructive: a nice addition would be an app that tells you the optimal angle based on time and GPS-location, using compas and acclerometer