MasterBeaker, is portalpal the occlusion tool you are working on? How long before it's done?
Right now the best way to do occlusion culling is by hiding/showing entire chunks of your level based on where the player is, with occlusion zones setup manually or perhaps a fast visibility check. Don't worry about overdraw; with modern graphics cards the key is to quickly chop the scene down into a reasonable number of polygons for the video hardware, as opposed to wasting a lot of time and effort nitpicking exactly which polygons can and cannot be seen.
Right now the best way to do occlusion culling is by hiding/showing entire chunks of your level based on where the player is, with occlusion zones setup manually or perhaps a fast visibility check. Don't worry about overdraw; with modern graphics cards the key is to quickly chop the scene down into a reasonable number of polygons for the video hardware, as opposed to wasting a lot of time and effort nitpicking exactly which polygons can and cannot be seen.