In doing my research to start building my own tarps I have stumbled on diygearsupply.com. Looking through the DIY pages I noted the Flat-felled/French (Hybrid) seam. To me it does not seem that this seam would be ideal, that there would be a slim chance for water to get through. The normal flat-felled seam with it's "clasping hands" design seems like it would reduce the chance of water getting through to zero. I know you all know more than I, please fill me in.