While the glue is drying it is a good time to cut the inserts to separate the bottles. Take the 6" piece of left over panel and cut it into two pieces that are 10 1/2" long. Now take the second piece of 2'x2' panel and cut it into strips that are 6" wide, or equal to the width of the piece of scrap panel. Odds are that it isn't exactly 6" depending on the kerf width of your blade it could be as narrow as 5 1/4". Just measure the scrap and make strips from the full panel the same width.
After you have your strips of panel cut make two more of them 10 1/2" long. Cut the remainder of the strips so that they are 8 3/8" long. These may need to be a tad short at 8 5/16" depending on kerf width and exact internal dimensions of your box.
In the end you should have 4 pieces that are roughly 6" x 10 1/2" and 6 pieces that are 6" x 8 3/8".