I've heard (read) it said "the only way to learn how to cast bullets, is to cast bullets.". So practice, practice, practice. (when I started casting it was a good session when I got 50%-60% keepers and that steadily grew as I went on.
There is a ton and a half of good info right here and questions are happily answered. There are the classic texts like "From Ingot to Target" by Fryxell/Applegate
http://www.lasc.us/Fryxell_Book_Contents.htm. Of course the Lyman Cast Bullet Handbooks
https://www.amazon.com/Lyman-Bullet-...KQY?th=1&psc=1. And if you type in "bullet casting texts" on a search engine you will get many hits.
Common sense is at the top of the list for casting and safety. Pain hurts and melted lead is hot. You will get many, many suggestions on casting safety so try to eliminate the "Chicken Little" types and use common sense. Don't be afraid to ask questions here. Just about any possible question has been seen here and happily/accurately answered.
I have maybe 16 molds, (which ain't many compared to the long time caster here!) and the majority are two cavity. I have never needed to cast 400 bullets in a setting as I enjoy casting and stop when it gets tiresome. One cool thing about casting is you can easily remelt your mistakes/culls and only you know your faux pas.
I would suggest you hold off on powder coating and get good consistent bullets first. No need to add to the learning curve. Casting adds a whole new world to our shooting/reloading hobbies and I have learned a lot. One even gets to know a lot about their guns by casting and processing bullets for a specific gun.
My "suggestions" are; Go slow. Double check everything. Use common sense and be safe. Most of all, have fun!