Noreal progress has been made, as I had other projects pop up. I did cut some sintra to wrap around the main body to tie it all together. I'm hoping to get back to it soon, as I want to hide a camel back in the main tank and possibly an MP3 player and speaker in the side tubes. Multi Purpose.
It's drywall tape wrapped around it. held it tight while I was gluing it. The plan is (as mentioned above) is to wrap some sintra around it and the fill in the gaps with expanding foam. keep it light but durable.