Well, I'd say, Lightweight is the perk to go with. If rushing, you want to get to the enemy's face asap, and you will be doing fine using it. If you think you might be running into claymores: This might be the case sometimes, but Lightweight will save your live in some different situations, e.g. running for cover. I've used such a rushing class in CTF where like 5000 claymores are set at once and at the beginning I tended to die a lot from them, but I quickly learned to be a little more careful about claymores and so I succeeded with this class, so in my opinion, you should give ot a try

And, by the way, using Lightweight is also a big advantage in gun fights because by moving faster, you are a harder target for the enemy.
Of course, you can also use Flak Jacket or even Ghost (which is a really great perk used in the right way) to rush, but I would prefer Lightweight. Maybe you should try all of them out to find the class you're the most comfortable with