Cool-I'm hoping the #8 coil zipper I am ordering will be just as water resistant as you've experienced. I'm planning on two double pulls so I can pull down from the top to help in venting if need be.
I am hoping to place my order later this week. I have a boat load of stuff in my cart at RSBTR, including stuff for this project as well as a tarp, pack covers, quilts, and whatever else. I've gotten some good info from the staff there when I asked some questions, including info on the silpoly. I was told the 1.1 silpoly PU4000 was specifically made for use in tent floors. I was told the standard 1.1 silpoly is very good for most any tent or tarp application. I also figured out the HH is higher on the XL silpoly than the standard width, but not as high as the PU4000. So, I'm planning on going with the 1.1 silpoly XL for the body of the tent. I'm also planning on about 7'3" peak height which should give me a bit over 50 degree wall angles.
I'm waiting to hear back about seam sealing either the HyperD 300 or Robic 420. They're PU type materials and I'm planning to use one of those (per their suggestion) for peak reinforcement. Normally, those materials are listed to have seam grip used, but the standard silpoly is listed for sil net....so I'm trying to figure out if there's a problem with using the two together. I also saw they sell stove jack material, so I'm going to order some and make my own jack.
Jeremy