no one has replied yet so i'm going to add my own experiences as my guild progresses.

I just hit guild lvl 40 last night.... it took a week of grinding writs for about 1 hour a night weekdays and a couple of hours on sunday. 30-40 went by pretty fast and once again i was surprised. With the next expansion just around the corner and being the goal oriented person i am i think i will grind these writs for as long as i can take it. For now... onto 50!