My concern, I guess, is that your posting this question (and follow-up) signals that, on some level, you yourself are less than confident about this watch. And $13,000 USD is a lot of money to drop if you're not sure. And, in my experience, if you start out with doubts, they seldom get smaller after the honeymoon phase ends. And, although the summer blue is admittedly less common than the other options, the preowned market is soft and saturated with Ultra-Deeps being offered at about 2k under retail and just sitting, not selling. I would not assume that this will be an easy watch to move for an acceptable price, should you buy it and decide you don't like it. If you want a realistic "exit price" (as in what you could expect to get for it if you do bail), perhaps try getting an estimate from DavidSW and/or a few of the other prominent resellers---it's a little white lie to give them the impression that you have the watch and are looking to sell it to them, but really it only costs them a couple seconds to give you an email offer. Hard to know for sure what they'll say, but I'd guess the watch will lose 40% of its value the second you leave the store, unless you're willing to be very patient and risk a private sale. That's an expensive mistake.
Just trying to provide some "wisdom" bought with experience. I've purchased a few watches over the years that I was initially hesitant about. In every case, the trajectory was the same: 1) hesitation 2) impulsively overcoming hesitation and buying the watch 3) monthlong honeymoon, convincing myself and others that it was the right choice 4) realizing that I've fallen completely out of love the watch and that my hesitations were justified 5) selling the watch at a substantial loss. Unfortunately, with such a new piece, you don't have the saner option of trying to get one preowned at closer to the "exit price," so that even if you do bail you won't get hurt too badly.
Nowadays, I try (sometimes unsuccessfully) to live by a self-imposed rule: if I want a watch, I won't let myself get it for a very long time--months if I can manage it--just to see if I still want it after that 'mandatory waiting period.' More than 90% of the time, I don't.
But... grain of salt.