If you have extra outboard housings this is not to hard to do. I first cut the back off of a used inboard and then used a grinder to the outside edge till it fit inside the other. The original hole is offset and I am not sure why that is? I also got a thin fender washer that fit inside the housing with a 1/4 ID hole. I used a hole saw in a drill press and cut the hole in the washer. Using the washer, the hole will be centered instead of offset like original. I am unsure if I will use the original offset back or the washer but either way, I will have to file the hole on the back of the outboard housing larger so that the head of the socket will fit. It will look better with this washer on the inside of the housing but if you bonded it to the outside you would not need to file the hole in the housing. With the washer on the inside of the housing I do not think anyone could ever tell after installed. This method will set the bulb 1/16 inch closer to the lens but I sure can’t see that hurting anything.