Don't get hung up on "instinctive". Some kind of aiming system will get you on target faster and more consistently.
Over time, with practice, aiming will become "instinctive"--you won't have to think about it and it will happen almost instantly. One of the best areal shooters I know is a "gap" shooter--he's done it for so long and practiced so much he can do it in an instant.
Don't let anyone convince you that you can't shoot a moving target or have to know exact yardage if you use an aiming system.
It may be tricky at first, but we all have to limit ourselves at first. It's part of the learning process.
Chad