E can vary quite a bit during the peak times. The line can look quite long when you go to check-in, and be near empty when you go to security. Or vice versa.
But, I don't think E is too busy at the times of your flights. I wouldn't expect the lines to be longer than 15-30 minutes, but I would guess it would be less.
Overall, BOS has been fairly good the past few months. Nothing like the terrible lines at MDW, etc.