I am going to be moving to DCC this spring with my layout and am looking at decoders for my track powered locos, particularly my Bachmann two truck Shay to start with. I see that there are 3 amp and 8 amp model decoders available. Which one(s) should I be buying??? My layout does not have any real up or down hill grade to it, therre is one short uphill grade that is about a 1.5-2% grade and I don't plan on running long trains either so current draw shouldn't be a big added issue because of those things but what about flat line running?? not sure what rating I should be buying...... HELP PLease!!!