Second:

Each 6" width of Flite-Metal is applied in exactly the same manner. Each 12" width of Flite-Metal is applied in a different manner from 6". 12" Flite-Metal is intended to provide the additional width required for an "individual" panel larger than can be covered with 6" width Flite-Metal...PERIOD.

12" widths of Flite-Metal (FK/FM 125 and 1210 packaging) are not intended to be cut down to 6" widths for use in-place-of 6" widths. This is an exercise in false economics because of waste factors with the use of 12" width can be as much as 40% because dead soft .0015 inch thick aluminum will stretch.

Single greatest Flite-Metal attribute over aluminum gutter tape or air conditioning tape is its capacity to stretch greater than 20% of its surface area. Stretch of a 12" by 12" piece of Flite-Metal can exceed 20% if it is not applied per our instructions. Work from the center and right angle to largest contact patch line outward to panel perimeter of 1/2 a panel at a time.

Some customers have reported applying 12" widths by peeling the backing off a single edge then slowly applying Flite-Metal to the surface "across the area" of the panel. This will work sometimes, but more often than not, it does not permit working a compound curve because the area mass is not being applied proportionally out to the perimeter of the panel. (You just might want to re-read that paragraph :^) Re-read it with the thought in mind that Flite-Metal will "always stretch".

A parity to the application of Flite-Metal is found in covering with plastic covering films where the adhesive is heat activated with an iron. If you have ever covered with plastic film...you must deal with the accumulative stretch of the heat activated film caused by the surface contact patch being the size of the iron. Over time, you must learn to pre-heat ahead of the contract patch to prevent plastic film cupping under unheated portion of  film. Is this an simple example of accumulative stretch?