Wow! I hear so much on the web about CAD standards, and it's always a real hot-button of a topic. I set up the standards we've been using (with very little change) for almost the past 14 years.
About 10 years ago we bought up another engineering company and rolled it all into ours, except for their retiring owners. We were 4 guys at the time, and we took on 6 more people, getting 4 CAD guys in the process. It wasn't cheap, and we had to move to larger offices, but we did it to grow.
We'd bought their assets and we'd given them jobs when their company was essentially closing up, but I could never really convince them that they needed to learn and use our standards. I guess that because there were 6 of them and 4 of us that they thought they were going to set the standard.
One big problem was that our standards were optimized to make it easy to draw from the command line, and these were mostly point-and-click guys. (Plus their drawings kinda sucked.) I tried to get them on-board by incorporating a point-and-click interface that supported our standards, but it didn't do the trick. One by one we lost all six. Oh well...
Along the way we picked up 5 new and more willing people, and in the end it all worked out.