Sounds like you're off to a good start!!
I've only been reloading for 2 yrs, but my procedure for a Handi starts by picking a powder that provides good velocity with the lowest pressure, sometimes you have to give up a little velocity for less pressure, but looking at load data that provides pressures will give you an idea of which one to choose, but not all data sources show pressure. Most sources also show the most accurate powders for a given bullet, one more clue to an accurate load.
Once I pick the powder and bullet I want to use, it's just a matter of putting the components together in a usable package, using the recommended brass, primer and bullet. Determining COL, which in a Handi can be futile trying to reach the lands in most calibers, so most just use recommended COL and then adjust later if needed for better accuracy. The recommended COL is just a standard length that's been determined to feed thru all magazines and actions which in a break barrel action means nothing, but it does have a lot to do with the pressure that load is tested at, a shorter COL will increase pressure, longer with reduce pressure up to the point of engaging the lands with the bullet which will increase pressure again.
I check all my brass to make sure it's sized properly for my chamber, brass isn't all one-size-fits-all, sometimes it's too long or it can be too short which both lead to problems, the action won't close if it's too long and if it's too short, which is excess headspace, will cause a bunch of other issues that aren't good! Too long is easy to fix with a full length sizing die by bumping the shoulder back until the brass is flush with the end of the chamber mouth, or sticking out just a tad depending on your frame to barrel gap which adds to headspace. Knowing that gap is important on a Handi, how to determine the gap can be found in the FAQ under barrel fitting. Ideally the gap will be tight on a .001" feeler gauge blade, but .002"-.003" isn't out of the ordinary. If the brass is recessed in the chamber slightly, in addition of the gap, this leads to problems and needs to be corrected.
I use the recommended start data for the bullet and powder combination creating loads of 3 each in ½gr increments up to within 1gr of the max, then drop to .2gr or .3gr increments to the max load. 9 times out of 10, I reach an accurate load somewhere in the mid to upper range. After each shot you need to carefully check for pressure signs, usually in a Handi, the first sign will be sticking brass, assuming it's not a dirty, oily chamber or brass causing the problem.
My way isn't the only way, just how I learned and it works for me. There's also the ladder method which I've never tried yet.
Tim
http://www.mikeswillowlake.com/ladder%20test.htm
