A MEC 600 Jr. is a good choice. It's easy to use and about as fool proof a loading system as you're going to find.
Another good acquisition is the Lyman Shotshell Reloading Manual. It has excellent step-by-step instructions on how to load shells with a MEC and an assortment of good information and recipes.
Do not depend on the bushing charts for your powder drops. Weigh them yourself. You don't need to weigh every load. Once you get the powder drop you want you might check every once in a while but nothing more is required. Don't worry about a half grain or two either way. It's not as precise as rifle reloading.
Loading 28 presented a couple more challenges than loading 12 gauge but none were insurmountable. Here are somethings I discovered along the way.
I use Winchester AAHS hulls with Claybuster replacement AAHS or AA wads, Winchester 209AA primers and Alliant Unique. My advice is to buy a flat of factory shells, shoot them and use the hulls. When you buy the shells check the lot number for an X or Y. These indicate more recent production and the hulls are slightly longer and load better. In the first runs of AAHS, the hulls were shorter and don't load as well.
Avoid Federal Gold Medal hulls. Some shooters including me have encoutered hull separations. FWIW, the Alliant site no longer lists loads for GM hulls.
Cheddite hulls (Challenger and Kent) are quite long and don't crimp as well as AAHS.
Two other suggestions are to listen carefully for the shot falling through the loading tube. Sometimes it can get caught in the tube and if you don't realize what has happened you end up with shot all over the floor. Secondly when in the first crimping station have one of the crimp points at 12 o'clock to ensure proper crimps.
There is a wealth of information on Shotgun World reloading forum and lots of good info on loading the 28.
http://www.shotgunworld.com/bbs/index.php
