I have fully sheeted several wings and the method I have found that works best is to edge-glue all of the sheets first.

Before I go any further, I should explain that the design of the wing itself is important. An ideal candidate for fully-sheeting is a wing where the sheeting overlaps the LE and TE, or at least the TE. For example, on an Ultra Sport, the sheeting butts against the rear of the LE stock, so it is easier to sheet just the front section first, then sheet from the spar, back to the TE.

But in either case, pre-joining the sheeting is key.

The way I do it is to lay two sheets together and check for a good match. Cut or sand them if needed for a good fit, but it doesn't have to be perfect.

Now I tack-glue the two ends together and (With the sheets on a piece of waxed paper) sand the top of the sheets where they meet. This will allow sanding dust to fill any gaps. Wipe away any surface dust and run a bead of thin CA along the seam. The CA will wick into the dust to create what I call "Balsa Concrete". Now, IMMEDIATLY sand the area with a sanding bar - The CA will ruin the sandpaper after only a few seams, but the joint will be perfect.

Now you can sheet the remaining section with one wide sheet and trim off any excess