Pics:
Above: the gaps! It's no Lexus.
The 3 mm weatherstripping. I cut this in half, width wise.
This worked out quite nicely: the strip was just the right size so I could position it in the gap and peel the backing off with it staying in place. Then I lifted up on the bumper to squish the adhesive down nicely.
Top view: the hood presses lightly against this.
No more business card size hole in the front of the car! Mercedes, eat your heart out.
I need to finish the quarter panel gap around the side marker portion of the assembly. I'll just use black silicone there since it's too small for the foam strip.