Yeah, good ideas, Smurf.
I learned the first time, when I went to check my oil, that you don't want it actually attached to the hood! LOL!!! But, no sweat - attaching to the top of the grille trim and the areas over the headlights works fine (with duct tape, at least)
Using 3 sheets could have an added benefit of reinforcing it at the joints by having double thickness there. This would help resist the oncoming air from pushing it into a concave shape at speed (although, I seldom drive "at speed" anymore once I found out how much better my mpg is going SLOW). I'd thought of putting dividers/baffles on each side of the grille to direct air, but then thought it would be better to leave it open so the pressures could "equalize" better. (maybe not an issue, though - dunno). On the other hand, those dividers/baffles could also act as reinforcement to prevent the potential concave effect. Maybe a win-win.
I've never tried it, but supposedly lexan and/or plexiglass can be bent with heat - around 200 deg. F, I understand. So maybe I could "customize" the "headlight covers" so they wrap around to the fronts of the fenders. I had been thinking the way to do it would be to put the whole thing in an oven (the one in the kitchen, of course), but the fiancee isn't too keen on that idea. However, a better option might be to heat up a big piece of pipe, lay the lexan/plexiglass on it where I want the curve, then use a hair dryer or heat gun while applying pressure & see what happens.
...Continuing the brainstorming out-loud...