Transitioning to a uniform sign

Our Association has proposed an amendment to require uniform real estate signs. While we still have a few weeks before the voting ends, our CAM has informed us that the homeowners are voting in favor of the uniform signs. There are many communities in our area that have required standard real estate signs, but all of them (that I know of) have had the requirements since the inception of the neighborhood. Our problem is the transition from allowing the current real estate signs to requiring the uniform signs. From preliminary Board discussions, we are considering a 6 month transition period for existing real estate signs, and a 30 day informative period for all new signs. We are anticipating headaches arising from trying to track new/existing signs. One proposed solution is to have homeowners/realtors register signs to keep track.

I would like to know if any Association out there has ever tried to implement a standardized sign and if so, how did the transition process work?

Thanks in Advance,
Kelly