Whats the bulky set for Mega Banette, and then whats the offensive one with D.Bond? I've seen various sets on the ladder used successfully, and I've seen Banettes with D.Bond and others without. Ones with Sucker Punch, others without, etc.
What's the usual sets for it, and EV spread?
The thing with Mega Banette is that it can run a huge variety of sets effectively. Almost any combination of the following can pretty much work: Destiny Bond, Knock Off, Taunt, Sucker Punch, Shadow Claw, Will-O-Wisp; its truly up to you what you want to do. You should almost always use Destiny Bond when using M-Banette; if you're not, you're doing it wrong, as that is really the main purpose to use Banette in the first place. Usually, Banette sets kinda look like this:
Banette @ Banettite
Ability: Insomnia/Frisk
EVs: 168 HP / 252 Atk / 88 Spd
Adamant nature
-Destiny Bond
-Shadow Claw / Knock Off
-Sucker Punch / Knock Off
-Taunt / Knock Off
This is somewhat the standard for more offensively orientated Banette. 88 speed outspeeds 4 speed Cresslelia, and the rest is dumped into HP and attack. Like I stated earlier, this is extremely variable, and you can switch and swap most of the moves. I personally find D-Bond / Shadow Claw / Sucker Punch / Taunt to be most succesful, due to the ability to taunt walls and junk while maintaining a significant offensive presence, but the choice is up to you. Will-O-Wisp can be used somewhere, but personally I don't have an extra slot open for it. It is possible to run a more defensive spread by running WoW and Pain Split, moving some of the attack EVs to Defense, but in my opinion that is a waste of Banette's potential. Really, just put on Destiny Bond, and mix and match three of the moves I listed above until you find a set that works to your needs. There simply isn't a single "standard"