which winz ?a decent cat + grunts vs a dualer?

Both can win. :P

I'll reply on this, but I really have no idea how skilled you are at War2 or what you know. I'll tell you an ok cat rush to kill duals, it works sometimes, but if you come up against someone who has a lot more skill than you you will prolly get beat, and badly.

The key is, peon search! Find him early and see what he is doing, if he is dualing, get 8 peons on gold then get your mill and a 2nd rax, get 8 grunts, put 6 guys on lumber or so then double cat, move to his base, take out one base, then exp and hold up, you should put 2 more peons on gold when you get 8 lumber peons. then 2 more lumber peons, that is about the time you should get a 2nd hall. Do not go lvl 5 for this, go lvl 3. Then get hold, when you are upgrading fortress get your 3rd barracks. Watch for air, a lot of people on gowbne will do that if they are walled in, also watch for them to chop out so you can move in with ur grunts. Right when you kill their first base move directly to their next base, sometimes tou can kill them right then, it depends on if they were ready for it.

Exp again when you hit fortress and make sure you have some fliers to keep him from exping, it is also a good idea to look around after you kill his first base for an exp, in my early days I used to get killed if someone got to expand again. Just make sure to cut off his res and break him down, Good luck.

I've had a lot of experience with catting duals, and getting catted while dualing. It really depends on experience and skill. If you scout the dual early enough, you should be able to 2 cat rush him before hes got ogres. Any good dualer will have ogres and be chopped out to counter cats unless they come really early in the game. It also depends on the type of defense the dualer uses. It's easier to get ogres faster if you have only archers and guard towers for defense; If you have a cat or two you could be slowed a bit more. You should be going hold while your cats are fighting with the dual; You need to seriously cripple or kill at least one of his bases or you probably wont win. In theory, you should match or out tech him.

To fight a cat rush while dualing, it depends on the type of defense you use. If you have cat(s), then you can use them to stall for time, while you build towers, and/or grunts/ogres while repairing the buildings hes hitting. You want to keep him out as long as possible; unless you have 34356423 ogres in which case it shouldnt matter. If your dualing with axers/guard towers, then you should have ogres and be chopping out when those cats come.

It really depends how fast you can get ogres, and how fast your opponent can cat rush you.