Looks like you were busy in the cool weather this weekend! I see you took Theo's +30, added it you your estimate and tripled it! It's looking good!
Years ago Dad and I made a laminated beam for the garage door at the lake, and it sagged. When I worked for that steel company, I bought an "I" beam to replace it. We used cribbing and a bottle jack to get it in place. You're right about the pucker factor once it gets up above your head!