Good fill-out is key. Only you can determine what cadence and temperature to run at (and it'll vary with the alloy, so strive for consistency on that score once you've worked that out). Don't reject the frosty bullets, they'll work fine.
It appears that you've got a handle on the process - keep it going. The thing with external advice and reading books/articles is that at some point you gotta start doing it yourself and learn by doing. Empirical knowledge is often the best knowledge. Not all casting equipment is created equal, no two molds are perfectly identical, no two caster's temperaments are created equal, no two guns are equal, and oh-my-god no two homebrewed alloys are created perfectly equal. Lots of variables that we in our chairs a thousand miles away can't observe and comment on, so at some point you have to assimilate what you've learned and start making your own mistakes - and you'll progress via the more mistakes you make, if you learn from them.
Make notes as you go along. You'll soon be so far down the rabbit hole you won't remember every little thing you worked out. You sure don't want to repeatedly re-invent the wheel.
