If you haven't checked out BLACKULA727's (and company's) tutorial on face-plate mounting it might be helpful (http://www.405th.com/showthread.php/31352-Tutorial-Install-amp-Detail-your-visor). He and a couple of people have detailed how they've approached the task.
I think I have seen that tutorial, but it's more suited for motorcycle visors which hold their own shape. I'm going to be using a 1mm clear sheet of plastic, so I need it to be held with gaps of under an inch, ie, many small bolts under an inch apart (Impractical) or gluing around the whole edge. That putty would be ideal for making a lip, but probably too expensive and not guaranteed to work.
Your JFO looks amazing... I need to look into some dremmelling details and grooves into the pieces!
you can give your sheet a curved shape by heating it and hold it in position until it cools down (after its curved you can still use window tint sheet to give it color)
Do you think I should stick with the correct attachment or break the mould and go with the other one? Tell me which you prefer too!