This is a tough one.... this is actually the same point that I am at now with one of my groups. I've talked with the local chapter officer but I don't want to seem like a stalker. I would say (rough guess here) no more than a month. But i also would not say check in every week. The way a person's job can go sometimes, they could say I'll get back to you next week, have a god awful week at work, and honestly forget.
Oooops, I just re-read your post and realized you were talking about the length of time in follow-up with your national contact. Definetly give them at least a month if not 6 weeks. Also make note of convention dates (if applicable) so that if follow-up becomes necessary you don't email around or during that time.
Good luck with your journey!!!
