Things change over time - often not for the best.
Besides the fiberglass itself 'moving' a skosh, the weather stripping compresses, the pins in the hinges wear a little. And maybe every 100th time, the hood gets slammed down a little harder than usual.
And that doesn't even consider the Coriolis forces.
I'm thinking a little wide is better than a little narrow.
POST TRIP OUT TO GARAGE EDIT:
The gap at the front of my hood (under the handle) is about 1/8", but that seems a little tighter than when the car was new. I know I don't want it any tighter than that. The gap back at the other end (near the base of the windshield) is about 1/4".
That right there would get me kicked off the lawn at Pebble Beach.