I think it's a fantastic idea! If it works, it'll be a very (actual) practical use of 3D printed objects :) Can you put up some pictures/videos of an actual faucet tap before & after installation? Also, I don't think it's necessary to go all the way to 90% because "pure mist" and zero pressure water stream tends to annoy other family members (in faucet tap as well as in shower heads) and has a very low WAF score. Maybe one with 50~70% savings for now? Better to have lots of users with a lower water saving% than fewer users with high water saving% etc.. Just my two cents because I'm working on something similar as well!