Since I have started the grind for Apotheosis (The Strongest Ones Name) I have needed to do quite a bit of grinding/reclassing/weapon training. This topic serves as (my opnion) for the best maps for doing grinding and weapon training. All of these maps will be DLC. I am doing all of this on Lunatic difficulty.
The first few are obvious:
Money/Saving money
-The Golden Gaffe (money, galeforce makes it easier)
-Infinite Regalia for the Silver Card to buy everything at 1/2 price just keep in convoy
EARLY Grinding
-EXPonential Growth, after a few reclassings there are better maps
-Champions of Yore 3 - This is my primary map for grinding (due to no friendles to compete with). I grind just about everything here with MY average unit gaining about 16exp a kill with paragon netting about 2-3 levels per map. Weapon grinding is nice gaining about 1weapon level per run. Due to all that this is also where I do all of my Support grinding. You also will pick up the All Stats +2 skill book, which is nice for early grinding, and just a nice skill to have.
LATE Grinding
Lost Bloodlines 3 Is a fantastic map to grind after a few reclassings. Not only does it have quite a few more enemies than CoY3, but you get paragon, which is a very necessary skill for grinding.
This is just my opnion, let me know if there are better more efficent ways of doing this.