Thanks for the comments and the software suggestion. I picked this software, after testing about 6 others, and it has all the capabilities you mentioned. There are administrative problems when every message needs to be approved. People tend to want instant gratification and don't want to wait even a little bit of time to see their post.

The splitting the board into different topics is easy enough, but I've found over the years that it's difficult to keep 'on topic' and posts get criss-crossed.
Maybe for special events (Derby, BC, Saratoga meet) we can experiment.

Thanks again for the comments.