So Spring edition 1942 is the easiest to learn. Depending how sophisticated your grand kids are you may or may not want to start them on that game.
If they are already too experienced for that one if you had AA50 I would recommend that one since the ruleset is the best and not as complicated as Global 1940, Europe 1940 or Pacific 1940. Since you have Revised that would be my recommendation for a more complex game.
Glad you are teaching the next Generation!
