Thanks for the compliment, and for explaining the logic behind the build. I can see where you're coming from, but honestly that flotation isn't adding any safety unless the boat is capsized. Another downside is that over time it will get waterlogged-even closed cell foam.
Not saying you have to be exactly like me, but in your case what you did is pretty close to how I built my flush decks. My logic on cutting out the factory deck is not only weight reduction, but once everything is welded up tight, if the boat were to capsize, what you'll have is essentially a giant 'air chamber' up front, which will give you more flotation than foam. I've been unfortunate enough to have seen a few capsized boats in person, and all of em ended up upside down, with the outboard far under the water, and nothing but the nose of the boat bobbing above water. The boat usually seems to float at an angle from 45-90* when capsized.
That's the primary reason I think my design is actually safer than a deck filled with foam. Eventually the boat will prolly sink, because inevitably air will leak out somewhere, but I'm willing to bet the farm it'll stay afloat longer than foam.
But ya, it's pretty hard to bring yourself to chop up the factory deck and foam.