Next time if you have opportunity visiting Tokyo again, you can call the boutique before your trip asking for Boutique Store Manager Chika. She is super nice and professional, transferring from VCA Paris to Ginza around 2 years ago. Supposedly she worked for Cartier before.
Before I visited Ginza last October called the store a couple months in advance, and was able to connect with her via phone and then email, and message app. I asked her to reserve one Ginza special edition pendant for me to pick up by letting her know the arrival date. During all the months communication, she was super helpful even offered information for the restaurant or tour if we needed. I had great time visiting the store and picked up the pendant, and browsed all other beautiful items. Of course she was hoping I would purchase the long Ginza special edition necklace with combination of magic pave diamond motif, Alhambra and Byzantine, which would be over CAD$76000. Hopefully it can be done next time.