You could go MVB for an all inclusive basking area (it will need to be 12'' above the highest branch or so). Just a plain basking bulb or flood light would do the trick though if he has regular UVB exposure in his tank. Key outside the tank is just to provide a warm spot for him to return to when he gets chilly rather than a permanent solution. That said, if you want to provide an MVB go the whole way and pick up a Megaray or one of the good Arcadia rigs from Lightyourreptiles.