EV training my mewtwo/charizard (EXP share) and I'm wondering when I can know my EVs are maxed. Currently doing Special ATK EVs but before when I was doing speed EVs, mewtwo's level ups went speed +19, +14, +9, +4, +3, and by the time it was +3 I got about 30 more EVs then stopped getting speed EVs. So for special atk when will I know his EVs are maxed? My charizard has been getting +5-6 special atk, but the last 2 levels he only got +2 sp. atk.

I don't there is an effort ribbon in FR/LG is there?

You really should keep count of it, but if not you can keep EVing, and then when you think you're done, try getting EVs in another stat. Use a berry to reduce this stat, and if it doesn't work, your EVs are maxed.

Is there a standard stat growth, like will mewtwo usually get special atk +3 each level once sp.atk EVs are maxed? I know my level 65 charizard w/max EVs gets about +2-3 sp. atk each level... or where do I get this berry?

I think I can be certain my EVs are maxed now. I just level up my mewtwo off level 55 vileplumes (3 spa EVs) and got sp. atk +2.

I need about 18 or so Vileplumes to level, so 54 EVs, or +13 extra...

I wouldn't say there is a standard growth.
It all depends on the pokemon you battle.

As you know with EV training.

I would advise to keep track of the EV's if you don't already

The stat gain by EV is affected by level, so a small change in EVs may not be easily noticeable.

You can tell you have maximum EVs by giving your Mewtwo a vitamin in a stat you did not train (like a Protein) and checking the result. If Mewtwo gains EVs from it, just reset the game without saving and continue EV training.

If you really care about having perfect EVs and you have Emerald, or a friend with Emerald, you can remove the EVs there.

What I like to do when I wonder when my Pokemon' EV's are grown is I put it in the PC, take it back out, and check for any change in stats. Also, when you level up, check for any unusual growth in stats (example, when I EV train, the stat I train grows by 7-10).