Matt,
I think you're likely to find the T8 to be exactly the right size. As Woodsmoke has pointed out, after a few practice go's, its easy enough to put up on your own in a matter of minutes.
One tip for getting the top cap on is to lay it on the ground opposite to the door, behind the tent - take the guy line from one side of the split and take it around the correct side of the tent and tie it to one of the tent guys in a slip knot. Next, get the other guy from the other side of the split and take it around the other side of the tent - you should be able to reach the first cap guy line - pull to release the slip knot and you'll have one guy in each hand going around the tent to the cap at the back. Simply wiggle the cap up the back of the tent by pulling each guy in turn, until it crawls over the apex into position. Its a lot easier to show than explain but trust me, it works!
I also have an idea for a modified groundsheet, but thats going to take a bit of time with a paint program to explain - I'll add it to this thread later on if I get the time tonight.
ATB
Ogri the trog