Here are my hints:
1. get a pair of the -$3 RUBBERIZED gardening gloves at Walmart - the difference they make in helping you move the quilt is amazing
2. don't move TOO FAST... when you move too fast the back side of the quilt looks terrible - and it does look like tension problems - ask me how I know...
machine goes fast - you go slow :D
3. work at a big table or at least someplace that supports the quilt... don't let it hang off the front of the table ...
4. work in 'sections'... start in the middle - work down to the edge in about an 8" swath (more or less)... then go back to the middle to the right of that swath and work to the edge again... turn the quilt, go back to the middle...
That way you never have more than half the quilt under the harp...
did I mention not to move TOO FAST???? it causes tension looking uglies.....