Common sense and good advice I did not heed.

Break out and inventory all pieces. This will make you familiar with them. This way you do not grab the 1 1/4" sheet for the lower part of the TE when a 1 1/2" sheet is required. Or you do not grab the 5/16" square rod and glue it in the TE when a 1/4" square should be used. The 5/16" is used for the LE. This will prevent you from buying a 3/8" square rod and sanding it down to fit the LE.

Mind you, I did not make any of these mistakes. They could happen though!

Clear skies!