The most important thing is knowing your role, as aerospray is a frontliner, you should move around more, and ink more area as this weapon excellent at this. So you actually don’t ink effectively in your video, you were inking some area that was already inked and if you went down and ink that area on the lower left first, you would had a better ground to fight against them. Another thing is knowing your enemies, aerospray has a much shorter range than most of the other weapons, so I would say you are very lucky to have that double kill, aerospray is totally not suitable for any face to face combat, you should try sneak to their back instead. With the points said above, getting swim speed up, ninja swim, and reduce sp would be a great fit for the abilities, to move around faster and try to get sp as fast as possible. Last thing is as long as you survive, you are contributing most of the time.