Best missile mech?

[Diablo48]

It's a Trial of Position, a 3/5 mover, and can probably expect (given average movement modifiers and range) about 40 points per turn. It's good in a standard game, but this is essentially an arena fight, and I would favour canon dueling machines to tear it apart.

Remember that the OP mentioned a 2 gunnery with missiles.  That significantly improves the expected damage against most opponents and could easily win the match assuming there is enough open space to use the range of the missiles.

[Stormfury]

That was expected damage on 7s to hit. Even with a base gunnery of 2, medium range, attacker movement modifier, target movement modifier, and the cluster chart along with minor heat issues add up.

[lonewolfsyndrome]

The Bane 3 and 4 are theoretically the most damage producing cannon mechs printed so far and have already been brought up, however I don't know their availability to the Wolves. The Nova Cat B also is effectively the same mech, although 30 tons lighter. There are also the Vultures to look at.

The Thor/Summoner B may be your best choice as it has both LRM & SRM's while incorporating Jump Jets and  NARC.

[Diablo48]

That was expected damage on 7s to hit. Even with a base gunnery of 2, medium range, attacker movement modifier, target movement modifier, and the cluster chart along with minor heat issues add up.

I make it roughly 5's assuming you are up against a similar 'Mech.  2 (base) + 2 (medium range) + 0 (attacker standing) + 1 (target cover/TMM) = 5.  Remember the Bane is a 100 ton, 3/5 assault 'Mech so it is going to find a good spot to park, and it will likely be up against a similar machine which will be taking the same strategy.  You might run into something like one of the 3050 heavy omnis with a bit more speed which could push the numbers up to 6's or 7's, but in that case you will have an overwhelming advantage in armor and firepower which will more than make up for the reduced odds of hitting.