I've seen those fixtures... Inexpensive, but I wonder how long before the plating falls off... And I agree that the amount of light might be lacking on these.
I am amazed at the total lack of proper deck mounted stern lights. There are a few deck mount all-round lights, but no proper stern lights...
Anyway, I just got off the phone with Jim ( of J.M. Reineck & Son) and I've ordered a replacement glass dome. $25 + Shipping. I have my fingers crossed that it will fit properly...
UPDATE:
I have received the Glass dome and I am happy to say that it looks like it will be a perfect fit. I will post an update after the actual installation.