Stringer help

[hobson]

I'm at the point where I have to decide what I'm going to do with the stringers on my 20. I cut the tops off of the stringers and ripped out all of the old foam. My first thought was to pour new foam and reglass over the tops of the stingers. I've talked to quite a few people who said dont bother with the foam just keep the stringers hollow? Then I though about doing four stringers, they would basically be 3/4" or 1" where the sides of the box stingers and now with out connecting across the top. Another problem is I can't decide what to build them out of. I was highly considering using a product called aquaplas you can see it here.(http://www.piedmontplastics.com/prod...?ID=5&TYPE=417). I got a test sample and laminated some cloth to it and adhesion is great. The nice thing about it is it is basically like a plastic so it wont ever rot and I wont have to encapsulate the whole stringer in glass, I could just tab it in with some layers of 1708. Coosa, divinycell, or nidacore are also options. If you use a core like coosa is it a necessity to encapsulate the whole stringer with glass of can you just tab it in and coat the rest with epoxy. Any input, ideas, or help would be great. I have been doing a ton of research and I'm stuck on top of the fence right now. Thanks for all the help. Here is a pic of the stringer if anyone needs any visuals.