for turf war, it depends on what kind of team you have. if they're aggressive, spend your time painting, and put walls up for them. if they're painters, go for your strategy and rush to the center.
Flounder is my favorite map, and i know every nook and cranny. use the map's maneuverability to your advantage. paint every climbable wall you see at least once as you go. it doesn't need to be perfect, but enough to climb up if you're in a jam. if the center is taken, hug the left of the stage, and climb up that area left of the incline, behind the roof access doors. or climb over the wall, into the opponents' same area. just be sure to watch your surroundings.
one there, don't stand still. squids like to hop the wall, and surprise you. if no one's coming in that direction, paint up the roof area, and shower the lower alcove's walls with your paint. it's much tougher for them to get to you in the middle of either rooftop this way.
if the team's busy with fighting, go to their area, and paint over all their wall access points. then wait for the rush, 'cause at least one squid will notice. pick them off easily with distance and a splash wall, or just avoid them altogether if you have the chance. up to you.
after that, it's just about suppression.keep them painting the same area, and watch your back.