Found this page on a jp wiki-http://wiki.kanmuryou.com/shooting-girl/index.php?%E6%8A%80%E8%A1%93%E5%AE%A4
Seems pretty accurate for 1-star recipes so far. I haven't tried anything else.
No, just like with KanColle, while there are RNG elements, there are "hidden" formulas, one in which you get increased % of particular items being produced by a recipe.
For example, a recipe of 500-500-500-500 may produce Item BB, Item ZY and Item PQ, but it produces Item ZY 88% of the time. In other words, while this doesn't yield you Item ZY 100% of the time, it's a high enough percentage that players will gravitate towards that formula in order to narrow down to specific items they want produced.