I must confess that since its all words on a paper
Exactly!
I usually ignore the descriptions (even while writing a story!) in favor of the mood of the story and the character's character rather than physical characteristics.
Actually, despite the way you describe your Clark, the only image that comes to my mind whenever I see Clark or Superman in a story, is that of
Dean Cain! So it doesn't matter unless you change the whole person, as it happened in case of
Woody Samms in the episode
I've Got You Under My Skin 
