You also said Corvian started moving the ball when 55 was out of the game. I'm not sure that kid missed consecutive plays and was in the game until the end. Corvian moved the ball consistently.#55 is their best o-lineman, I've said as much myself. You're right that size doesnt say anything of talent or performance, but having said that acting like size isnt a factor at all is very naive.
You take a kid like #71 for example who is 6'5" 290 lbs and can move and has talent, it matters. If size in the trenches didn't matter college coaches wouldn't put such a premium on it in recruiting.
Starmount has been undersized against many offensive lines this year. What I've seen from them so far, size has no impact.