Buy haven, even that 7% reduction on all shots may mean that strix must take 3 shots at you instead of 2. This is massive since you have way more time to attack him. Buy nimble since it increases your movement speed making it easier to strafe.
Pick champions who are midrange or short range since strix will have to move his scope much more to keep up with you. Good champions are Skye, Jenos, Viktor and Tyra. Since they have massive DPS short range and their drop off is not that bad.