I had the same goal when I began building my current breeding colony. Really the best way to be sure you end up with an adult with nice blue stripe is to buy a color changed yearling. This way you know exactly what you are getting. The next best way is to get a CB baby from parents who have the "look" you like. It's best if both parents have the trait you are seeking. BTW, as far as blue stripes and locality goes, Biaks are probably the least likely to have a nice blue stripe. If you want blue-marked chondros, look for lowland localities like Jayapura and Sorong. Also--since most locality claims are BS, go with what you like.