what jets should i get for my Stage6 R/T Mk II PWK Racing Carburettor ?

Baught my aerox the other day and it Boggs around 25mph like mad? Got a lot of body upgrades but has nothing to do with that and my engine: has 70 kit on I think and it has stage 6 manifold' stage 6 open air filter, c16 exhaust no baffles and Stage6 R/T Mk II PWK Racing Carburettor and I think that is my problem the carb not sure. it's a 24mm and I think it's just to big? i would prefer to keep this carb and thinking of just jetting it down? took the 2 jets out (big and small one is there anymore? and witch one do i change?) and the big one has no number on it that i can see but the small one has a 38 on it anyhelp? what size down? and wtich jet am i changing or both?