Derby Extra. This is a very smooth blade and it is rather sharp. It is a nice beginner blade. If the Derby is to sharp, try a Shark. A Shark blade is also smooth but not as sharp as a Derby IMHO.
My vote goes to astra platinum
I'd go totally random. Just reach in and grab one without looking. And hope that you draw the Astra's first!
+1 give these a try first. If you're not liking them, then go to Derby for the next shave.
Ps. Lusitano are you Portuguese by any chance?