Here are some pictures of a small standing seam roof we did not long ago.
https://flanamullegan.wordpress.com/As for special tools it could all be done with one set of adjustable seaming tongs (like hand held metal brake/tongs)
https://www.stortz.com/product/stortz-adjustable-roofing-tong/ I just picked up a pair at a junk shop for $15
And a seaming iron and wood mallet for completing the folds/seam on the roof.
https://www.stortz.com/product/ese-hardy-tool/There also all sorts of nice fancy tools but those are all you really need for a basic roof.
This design for completing the seam on the roof has been around for I think over 100 years, I've picked up a few at junk shops quite cheap though new ones are anything but.
https://www.stortz.com/product/444-a-burritt-seamer/We used 24 gauge galvalume that came in a large roll, 10 squares, and cost ~$800 delivered. Weighed a lot, moved it with the forklift. Advantage over using 10 small rolls is less waste, lots less depending on your pan lengths.
Not sure how suitable galvalume or even galvanized is for your location but they do offer stainless roofing suitable for standing seam, and while more expensive I expect would be great in the salt air.
Grigg
