Am new at this so if I foul up....anyway have carport off garage 2/12 roof w/2x8s 24 oc. and 171/2 ft. span, (I know, I bought it that way, should be 2x12s) we are getting record snowfall this year and I hope to not have sagging 2x8s this spring. Talked to an engineer at Simpson, he said their...