You're better off 4 Goku. Having 4 Goku is one of the most effective english Kagero decks more so than Overlord. 11k defensive, but you can only get off with his effect once to twice per match, and 3CB just to lose Twin Drive and slaughter RGs with a possibility of being blocked to cancel the effect isn't as rational as, say, 1CB to kill a Grade 1 and Soulcharge, 2CB to kill a Grade 2-0, or Drive Check a Grade 3 to kill a Grade 1 Booster.
After that, Heat-Nail Salamander in BT04 is a more suitable replacement than Berserk because of the recycling effect with the ability to still kill boosters.
I'd say a more proper English deck pre-BT05 (I don't even want to acknowledge The End) is
4 Goku
4 Waterfall
While Goku is best Early Game, Waterfall can manage itself with a conditionless 13k offensive to Vanguard if you're forced to ride it Early Game. And it helps unclog your hand with the G3s you don't need once you Ride it Late Game.