Pull the sticks first, saves hours every time.

Did you learn that trick from me or what?

Read a post from an old installer on a flooring forum a while back saying the same thing, that over stretching kills your seams because the backing is fighting the latex all the way. Made sense to me once I thought about it. Carpet needs to relax into the tack strip, not get strung out like a guitar string. Your Portland job sounds like proof of that. I would say keep doing what you are doing but just watch the loose spots and wrinkles over time, since there is a line between eased in and sloppy.