JJKK's base

With that canon under upgrade at the back, I would use the gunboat to remove the 3 boom canons furtherest from the shore. Then I would put TMeds around to the left and around to the back. Stay out of range of the remaining boom canon that is closest to the shore and work down to the rear of the base to destroy. This all assumes you have decent GB, TD and TH statues to counter the statues that "jjkk" has. If you can't remove the 3 boom canons, remove the one in front of the base and the one in the middle. Go around like I said before and use your shock bombs to disable the boom canon at the back then flare to it and destroy with tanks. In any case, good luck!