For those building their Eclipses, here's something to keep in mind. I have been playing w/ the cg on mine and have settled on it at the rear of the wing tube. (about 6 -3/4" from leading edge). This is of course personal taste. This is with the wing moved back 1/2" from stock. With the wing in this position, you can figure every 1/2 ounce in the tail moves the cg back 1/8". Still very happy w/ the way it flies. Thanks again to Steve for all of the tips in this thread.