The Tank you Want.....
can be got from West Marine...sku # is 153445. It fits nicely in a stainless steel fender holder, sku #190647. I would add a bungy hold down. Total time of installation is about three and a half minutes. I can never, for the life of me, figure out why people go to such agonies over custom propane lockers or tank holders as these look really good, are ready made, and comparatively inexpensive. The tank MUST be aluminum or you will need to buy some rust remover, to combine with elbow grease, in the future!