Centering Map to view all the points
What you can do is set an invisible point that is in the middle of all the visible points and the map will center on it and then adjust the zoom level to view all the visible points.
To set the default invisible center point open your wagmp_map_1.php and find the line map.setCenter(point, 13); and change it to map.setCenter(new GLatLng(X, Y), 13); where X represents your invisible center point's latitude and Y longitude.
Please note that that there are 3 instances of this line in your map file so change all three of them. Hope this helps.
Also see the above post how to adjust the zoom level.
This feature should really be available in the Pro Maps wizard along with the zoom levels so that no coding is required to adjust them. Hopefully in the next version soon.