Applying Edge Molding

I'm starting to think about the edge molding which will be applied to the roof corner encompassing where the roof meets the side wall. My roof and sidewalls will be covered with .040 aluminum sheet which I intend to adhere with Wilsonart contact cement, so NOT floating the aluminum. I recently purchased a piece each of two styles of edge molding from Vintage Technologies (see attached) to kind of get a feel for which one to use. One molding has a 5/8 inch leg that wraps around the side wall and the other has a 3/8 inch leg. I'm thinking the 3/8 version will be easier to bend around the curved surfaces. I have a couple of questions.
1). Aside from the 3/8" version being easier to bend, is there a good reason I should rethink using the 3/8 inch version and consider the 5/8" version?
2). What are suggestions for putting under the molding, between the molding and the aluminum skin. I've watched a few YT videos and one person uses butyl tape.... another uses VHB tape... so any help there would be appreciated.
Any other suggestions on how to apply the moldings would be helpful....surprisingly there's not a whole lot of installation instruction that I could find.... so any help would be great.
Thanks.
John
1). Aside from the 3/8" version being easier to bend, is there a good reason I should rethink using the 3/8 inch version and consider the 5/8" version?
2). What are suggestions for putting under the molding, between the molding and the aluminum skin. I've watched a few YT videos and one person uses butyl tape.... another uses VHB tape... so any help there would be appreciated.
Any other suggestions on how to apply the moldings would be helpful....surprisingly there's not a whole lot of installation instruction that I could find.... so any help would be great.
Thanks.
John