This one is 72 1/2'' x 90''.Woooahhh!!! That's big!!! I would be nervous too!
The biggest I have quilted would have been The Opus at 80" square ... just take it very slowly and you will need a walking foot. I baste with 505 spray and a few pins at the outer edges and have never had a problem.
Some local quilting shops offer a layering service for a small fee (or sometimes free if you purchase the 505 etc from them) and with a beast that size I would heartily recommend it, personally I wouldnt have enough clear space to layer him and the layering (for me) is the most dreaded part .... again because of lack of space I suppose.
BTW There is NOTHING wrong with quilting straight lines!
Cant wait to see your pics!