Google Map Client Side Clustering

I need a client side clustering solution for an existing google map that loads slowly due to too many markers. Use of the google markerclusterer found here would be ideal - [login to view URL] - Clustering must improve load time - Original functionality must remain unchanged - New js must have example code in it to include custom marker icons if required in the future. - Code changes clearly commented as code changes will be reused on other maps on the website.