First off let me say that I have nothing more than a passing interest in avaiation. I fly a sim ocationally and have a fondness for complex and mechanical things. I read this formum ocationally because I am interested in how people approach problem solving, particularly in time critical situations. The 'infomed' speculations are as interesting as what eventually turns out to be the facts.
Ok, having said that, I also read a forum for professional photographers at
http://www.sportsshooter.com/index.html
They faced a similar problem of wanting to exclude non-professionals and how to vet the appropriate people where "appropriate" is hard to define.
There approach is to make the forums viewable by all but only approved pro's can post. There veting process is what I think might be of interest. They use a referal system. Esentially, you must be "sponsored" by an existing member. If you "sponsor" someone that is not appropriate, both of you loose privilege. Presumably, you would have some way to seed the population.
I would hate to see this new forum not be viewable by myself because I think that only the Un-informed speculations would be left for public viewing.
Good luck in finding a solution to the excess bagage.