Re: [Nutaku] Armor Blitz
Based on the experience of mobile players, you get one or two 5* from blueprints per month. However, it's when the portal of chaos is open (because it yields lot of blueprints, something like 400-500 per week with a good team).
Anyway, you shouldn't waste blueprints on 3* and 4*, keep them for 5*. The factory is really generous (4x 4* already, and it didn't ran yesterday because I was saving for the 4th scouting slot).
And since blueprints are basically "I want THIS 5* and I get her", it's obvious why it shouldn't be readily available after 2 weeks of grinding...