this depends lukebozek1 on mainly how the leading edge is built. if it is built like this plane, where the is a big balsa stick that is the leading edge that is to be sanded, than covering that end is much easier. the problem from there is the trailing edge (at least on this plane) for the top, i just used dots of full strength glue in the center tops skips a few ribs at a time. the back is where you really have to cut the tissue so it bends nicely and make sure the glue is on on the string and the back of the rib, otherwise it wont stick and it will look sloppy. i followed the bottom in a similar mannar.
in short, the answer to your question is, i put a fair amount of glue (thinned) on the bottom ribs, to the back bottom spar. from there i switched back to full strength after the other glue dries, and proceed from there.