It's a bit late so I can't address your post in detail but a few things stand out.
Firstly, I strongly suggest dropping the whole "line of ...." and "persuading" angle. Admittedly that may be useful in getting a job in the first place, but when it comes to actually
earning someones business, you're gonna get left behind by salesmen who's method is rooted in product knowledge, professionalism, honesty, delivering upon commitments and actually caring about a customers needs.
As arrogant as it sounds, I've been eating fast talking, couldn't care less, nil integrity salesmen like that for breakfast for years. This kind of salesman has made me so much money over the years by making it so easy for me.
You can only take it so far if your technique is rooted in minimal identification of a customers needs and a threadbare product presentation. As a consequence, you'll spend all your time negotiating instead.....and the price is always going down. You'll make $50,000 a year working six days a week and barely make more per hour than you are now.
And if you don't close them they are not coming back. Instead, they meet a salesman who is constantly asking questions and not talking, is building a relationship of mutual respect and mapping out a path to get the customer off the bus and into a car that genuinely meets his needs. As a consequence the negotiation process is a brief one, gross profit is retained, customer is happy and salesman is on the way to making $200,000 to $300,000 a year, all by actually giving a s.... about the customer. Sweet deal heh?
You clearly have confidence and drive......use your powers for good, not evil, and clean up in the process