with the door on, your peripheral vision is less effective so if you can take the door off you will find the astar easier to get used to. that doesn't help you in the winter if you do winter longline ops but with practice you will get used to it either way.
our fleet has varying sizes of LL windows ranging from the original eurocopter (small) to chinook (large) to the new eurocopter/airbus (largest). they can all be used in production work and it takes some adjustment going either up or down in size as the sight picture changes. one thing we never change at our outfit is the LL length. 150' seems to work in all of the environments that we work in.
cheers
fp