FWIW, I have experience with Tyvek housewrap, not as MYOG but in construction. I've also made large scale sewn inflatable sculptures with a cheaper Tyvek alternative called Barricade. IIRC, both wraps can be left uncovered and exposed on the side of a house for up to 90 days without harm (ie still perform up to warranty); I've left them quite a bit longer than that on western exposure and in winter without any problem. Both kinds of wrap weigh 6 grams/ft^2 on my scale, or a bit less than 2 oz/yard^2. So heavier than some silnylons.
Tyvek housewrap is pretty stiff and noisy. I can break a strip 3/4" wide pulling with moderate force, and easily tear a sheet with a small starter cut in the edge (it tears with the two layers separating). Barricade, by contrast, is a little softer and quieter (but not like cloth) looks a little like woven polyethylene tarp material (eg, cheap blue tarp) but thinner. I can't tear either a sheet or a strip. The sculptures I've made are sewn with a zig-zag stitch and Gutermann upholstery thread; I've never had a seam fail. I can see the pores in Barricade, so doubt it's very waterproof, just strong, light-ish and cheap (about $1/yard in a 100' roll). My local lumber yard gets stacks of lumber wrapped with a very similar material (identical?): they give it away free, or throw it in the dumpster.