Will you judge based on reproducibility? You seemed to have hinted at that in the +bow example, but mentioned nothing in the technical criteria.
How about originality of design? I.e. many homemades from polycarb just utilize the standard +bow handle, would that detract from the score? More than using a nerf handle?
Yes, reproducibility is a judging criteria. A +bow was an example of a homemade that while a very sophisticated design, may score low on the reproducibility side. If one were to, for example, streamline the +bow design so that a monkey could put one together, that may score higher in reproducibility.
Originality is an extremely important factor. If its been done and posted, then its not original.