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ok. i'm on my laptop now, so here's a bit of advice for ranked matches: for the splattershot jr., your range is abysmal, so focus mostly on securing and defending the splat zone. in blackbelly skatepark, moray towers, and port mackeral (all of which have two splat zones), you could take a more offensive approach and lead an attempt to steal the opponent's splat zone. just be careful and make sure not to take your opponents head-on.
for the krak-on splat roller, you can play a bit more aggressively. just don't roll around all the time. this makes you eZ shooter bait. use your ink flick move to attack other peeps, and make sure you have your special meter filled if you want to make an aggressive move and capture the splat zone / ride the tower. speaking of tower control, placing a squid beakon on the tower gives your team something to jump to and / or absorb ink shots from your opponents, who may be distracted by it. as a bonus, you can also super jump as a kraken to surprise people that may or may not be attempting to destroy your beakon.
Usually I'm one of those players that likes to get as many points as possible, while getting a fair amount of kills. That's why I mainly use the kraken roller, and right now I love it. Thanks for the advice!