Let’s close with the idea of flight spares. The idea here is twofold. First, it is good to have a second satellite ready in case a mishap occurs to the first. Mishaps can range from rocket blew up all the way down to a mundane dropped it while carrying it to the truck.
Conceptually and more important, you want to build two or three satellites simultaneously for two reasons. First, you may make a construction mistake with one. Having a spare means you can continue work without having to wait for new parts or fabrication.
Second, you will build one better than the other. Statistically, one of your builds will have better performance than the other. This better one is the one you will fly. By creating multiple builds, you give yourself and your skills a chance to practice, hone, and ultimately create a better picosatellite.
So build two and fly the one that does best in tests.