Thanks for sharing this. I think you will be able to decrease set building time by 5-10 min per set once you refine and practice your process. Personally I never double check sets for accuracy. I used to have problems similar to those you mentioned with missing cards but once I stuck to the same process I rarely run into an issue. Also I agree with the preselling Topps Update sets comment. With Update (except for Master Sets) I usually take my time and sell them off slowly at BIN prices during the off season. They tend to hold their value better than Series 1 & 2.
"Show me a good loser and I'll show you a loser." - Red Auerbach