Boilerpig1,
Odd coincidence but I was given a Pacific 105 just this summer. It has 12 ga and 20 ga dies for it. I reload in 20 ga, 28 ga and .410 for skeet shooting and the loader will find some use for me for 12 ga hunting loads.
I would suggest you look also at the hodgdon powder web site at
http://www.hodgdon.com/data/shotshel/index.php and select a load you like. It is of course not necessary that you stick with just their powder, you might just want to peruse it for information. Alliant also has one that displays the use of their powders.
The best 20 ga hulls today are the Remington STS. Winchester "improved" their once great AA hull and the competitive shooters flocked to the competition in 12 ga and 20. The Win 28 ga AA HS hull and the .Win 410 AA HS is still the better one for reloading life.
That said the will all reload. The most economical hull to acquire IMHO, is the Remington Gun Club hulls. You can buy loaded boxes for around $3.50 and shoot you way into a supply of loads.
I would suggest that you look for a powder that will serve a number of loads for you. Wads are often specific to the load or at least for a small range.
I use Universal but the International Clays mentioned is also a very good powder. There is a wealth of information out there for you.