My general take on vehicle sizes from a low recumbent is that cars effectively become vans. It's not pleasant, but other than cars blocking your view so you have to edge out at junctions more frequently and your eye level being in the beam of everyone's dipped headlights, it doesn't really make things any more dangerous. The recumbent WTF factor works whatever your height.
A greater concern is wheel splatter, IMHO.
(If that's a Mirrycle then yes, it needs be done up fairly tight and likely re-tightened at regular intervals. I've currently got one on the new Streetmachine as the Rohloff means I finally have somewhere to mount it. I may revert to a B&M Cyclestar, as it keeps getting bashed when I carry the bike through the front door.)