I'm wondering what everyone think about housewrap and natural enclosure systems. For those who have infilled behind wood sheathing or siding, what type (if any) of building paper did you use? I'd sort of hate to throw up tyvek, but since I'm kind of locked into using osb sheathing (its available in the 10' sheets that I need, it'll keep the weather out while I get my act together, and its pretty cheap) I'm not sure what to put over it. 15 lb. felt is of course an option, though I'm not sure I'd be better off for using it. I guess not all sheathing would necessarily need covering, though 1/2 osb definitely won't last long unless covered promptly. Suggestions?