What is best way to key image sequence for output to PNG files?

Currently using AE 11.0.2 on Windows 7 machine.  I have captured a series of green screen stills and have inported the image sequence into AfterEffects through  Premier Pro usin 1 image per frame. I currently using a garbage matte and then using vibrance, and keylight to remove the green screen. Outputing to image sequence PNG files. No problem with any of that.

'

My question is what is the best technique to key a series of still images without setting key frames for each still if the talent has moved.  Would roto brush do a better job than the painstaking process I am using now?  Or is there a better way?

Thanks