For a 1 piece job, how about finishing the short side with the first cross and then tying. Then with the long side just start with the second cross and tie when you are done at the top? The way I see it, this is more symmetric than tying the last main on the short side as none of the shorter mains will loose tension when tying the knot. It seems simple enough, what am I missing? Does anybody see any drawbacks with this approach?