So the map.setCenter(new GLatLng(30, -98), 3); function does set the zoom, but it also centers the map on the latitude and longitude that is specified.
If you want the map to be centered on a different point, you should use this function to center the map. You will have to find the longitude and latitude of the location you want the map to be centered on. The openInfoWindowHtml will center the map on the marker that the info window is for however, so you will have to remove these function calls from your wagmp_map_[num] file to use setCenter for centering the map.