I haven't used it but I've considered it for a homespun quilt.
Where you looking on the Townsend's web site? I believe OS-350 is their stock number for that item. Townsends' osnaburg looks coarse and slubby compared to Dharma's. It maybe more authentic for the reproduction clothing they offer.
OT PS- If you enjoy history, Townsends has a YouTube channel with lots of great videos.