Quoted from Aldo
"Now here's a dumb question on my part: when testing my .45s, wouldn't I need to have them braced in a vice to eliminate the human element of hand-holding, moving the handgun when squeezing the trigger, etc?"
First there are no dumb questions.
The Chronograph will only have minute variations if any from not using a gun vise. I have one but due not use it when testing my re-loads. More important is that you keep the same distance from the Chronograph sensing rods.
"Next dumb question: using my digital scale, would I want to group my loads so that they are in exact same weight groups, especially since my overall weight of the reloads range from 321.4-323.8, or is that getting too nit picky (is that a word)?"
Yes nitpicky :adj Definition: overly critical, esp. on trivial matters;
focused on only trivial aspects
This depends how much time you have, by sorting bullet weight, brass brand and weight you will have more consistency in your reloads both inaccuracy and in velocity. Very time consuming. If you want Match Grade bullets than purchase them they will have the least amount of bullet weight deviation and do cost more.
"One more dumb question: my reload manual gives me the max amount of powder limit, but it does not give me the min amount, and I can't find that anywhere on the net for the powder I use. Ideas?"
Minimum powder charge weight is 10% less weight than the maximum safe weight amount.
Here is one good web site.
http://www.hodgdon.com/With information on three different powder brands, powder burn rates, bullet weight and charge weights.