The chosen manufacturer is 'AGWAY METALS Inc.' (Brampton, ON)
Chosen material specs: Type: AR-38 T SS F 19.92'' COV / thickness: 24GA / color: Galvalume Plus
This choice is driven by the shallow slope of the roof (5.88 degrees or 1.236/12).
The main benefit of this style of material is that:
1 - The metal panels are assembled with Clips (see below) so there are no screw through the material itself, therefore less risks of leaks
2 - The seams between two connected strips are 1 1/2'' high and get crimped to each other with butyl tape in between eliminating further the risk of leaks (see below).
The material comes in strips (panels) cut to size for the roof. In this case, the longest strip is 34ft long.
Note that it requires care for moving them around but with the 24GA thickness and the high seams giving them rigidity, it is quite doable and we had no serious problem getting them one by one up two ladders to the back of the roof. We were fortunate to have almost no wind conditions during the install. It could have been a serious challenge if we'd had windy days.
This diagram shows how the seam between 2 consecutive metal strips are crimped.
Note that Butyl tape is also added before the seaming operation.
There is no potentially leaky screw hole in the panels!