Nice tool Neil. I would push back that this tool is accurate for angled brackets (as shown initially) due to the thickness of the register or pilot stub (removing that thickness--1 mm maybe?-- skews the hole when drilled for the bracket riveting. Straight-on paneling, as shown later in the video seems to be that best utilization of this tool.
I personally would not use rivets on any panel that isn't load bearing. Just not necessary with todays bonding agents that are so powerful you can't remove them afterward. I would consider also having some panels easy removeable for access, so would use rivnut panels onto closed cell foam strips with no adhesive.
I could have used the strap duplicator a hundred times!!!! Ordering one this morning!
I was thinking about how to do I put the panels on my chassis when it arrives. When bonding alloy to steel tubes, how is the tube prepped? If you paint then is the bonding to the paint film? If to prepared steel, does the bonding agent provide the galvanic protection needed?