I got my tarps at Menards. If I remember right they were 42'x64', two of them worked out perfect. (building is 120' x 40') Don't get to HF very often as the closest store is 120 miles one way....
The first one I did with a tarp was over 30 years ago and the tarp still looks like new. And it don't rip when putting up by myself. Just a dumb farm boy!!
The only "triple duty" ones that I've seen are the Titan brand. Maybe they were made by Wilton?? I wish one could find more history on the Wilton company..
Purchase 2 older Linksys WRT54g Ap's, make sure they can use external antennas. Install DDWRT software in both. Run the one in the house as an AP,the one in your shop as a CLIENT. Outside antennas on both. Been using this setup in my shop for 5yrs.