I did spend a bit of time and thought to cover the 20x20 triangulation tube in the corner of the floorpan. As I've got dropped floorpans I didn't want to put a large folded panel in to cover this up as others have done - there's no 3mm steel bar across the floor to rivet too (1.6mm steel floorpan only), and there space might be useful. I mean there's nearly 100mm of depth there, doubling the luggage space in the car! Being serious it may be a useful place for a cabin fire extinguisher on the passenger side. I also wanted it to line up with the 40x40 tube coming from the front. As you can see I added a bent ali bracket to the 20x20 tube to pack out and stiffen up the panel. This is held on with rivetnuts and the bike frame shaped panel will be riveted to it for strength. I'm thinking I may add a 3mm rubber edge strip on the edges of this panel where it touches the floorpan etc.
Think I'm going powdercoated panels (which may bankrupt me), black rivets, either acid etch and paint the sealed ali ones I have, or going non-sealed (open) rivets on the interior, and painting or leaving natural closed rivets on the outside. I release open rivets aren't quite as strong, but I figure they won't be working at UTS anyway - the silkaflex will be doing it's job and many of the sections will be panelled both sides.