And that 12 x 15 foot tarp can be set up as a wedge tent, also. If you make up your uprights 6 foot high, and run the canvas over it, you will end up with a wedge tent about 7 foot wide at the bottom. If you set it up full length, you end up with a wedge tent 7 foot wide by 6 foot high by 12 FEET LONG - approximately. That's a lot of room! And the ends can be closed up with two other pieces of canvas, or even blankets. If you make your ridge pole only 8 foot long, you will have about 4 feet of extra tarp on each end to drape down to close each end off, and still have a 7 foot wide by 8 foot long by 6 foot high wedge. Still lots of room.
The Rev War British military tent was 6 foot wide by 7 foot long by 6 foot 2 inches tall with a small bell extention in the back for gear. This was a 5 MAN TENT - one on guard duty while 4 slept, and they would sleep perpendicular to the door. Low man on the pecking order slept across the front by the door, progressing on back with high man getting the back end.
So that 12x15 painters tarp would work very well to make a wedge tent. And it is soo much more versatile in how you want to set it up - like a wedge, a leanto, an awning, a diamond, over a dome of willow poles as a wickyup, or even roll up in it with your blankets beside the fire. And the price compared to a new finished wedge tent is something worth considering.
Just my humble thoughts to share.
Mike Ameling