I use different classes on different maps and for different purposes. So let me tell you something about custom classes. I don’t claim to be an expert of these things, nah, this is just what I think works, really.
If you want a wide spread K/D, it’s pretty crucial – among other things – not to be spotted and to avoid UAVs. I suggest you use the Ghost perk and the Suppressor attachment as far as possible. Well, if you’re playing as a team, someone could have the objective to shoot down the enemy’s air support. (You may take turns in this purpose.)
I want to be able to quickly swap to a pistol when the primary weapon runs out of ammo (which it does if you’re spraying a lot or just staying alive a little longer). And I think the B23R is the best choice, due to its low recoil. Unlike Modern Warfare 3, the secondary options in Black Ops II, can’t match the primary as main weapon.
As a lethal equipment, I use Bouncing Betty, which is faster to set than a Claymore. A con is that the enemy may crouch to avoid it. Still, the Bouncing Betty almost guarantees at least one dead noob per life.
Engineer perk is probably the most overpowered perk in the game: it shows enemy equipment through walls, delays triggered explosives (e.g. if you don’t need to stop on top of a Claymore, you could just ignore it and pass). And if you’re using the Care Package as a scorestreak, you can also booby trap the enemy’s Care Packages or re-roll the Care Packages content with the Engineer perk. This is cheese.
For me, the Toughness perk is essential. Without it, I lose too many one-to-one duels or gunfights.
I usually run out of ammo, so I need the Scavenger perk badly. And because I run Adjustable Stock attachment on my weapon, I risk getting a gun without when picking up enemy’s shit. And this is pretty chocking when you’re used to move fast aiming down the sight.
In the next part, I’ll post a screendump of my classes and break ‘em down for you.