The samples looked the same under the showroom grid and will not look the same at four in the afternoon in their kitchen. You need a yes on a cabinet colour or a floor stain before the lead time eats the install. Your assistant wrote "both would be beautiful." That sentence is true and useless.
A finish choice is small on the page and large on the walls. Write the small version so they can own the large one.
Two finishes, one room, what you give up
Close the list. Option A, option B, where each goes, what it does to the next room if they want them to relate, what it rules out once the order is in. Then your recommendation and why you would flip — they cook every night, they want the room to read quieter, the sample they loved was the one in daylight.
One room per message unless the same pair covers every surface. A whole-house palette in one email is a meeting. Respect the time they have: they should be able to answer from a phone between two other decisions.
Do not attach the board. RelayLink does not carry attachments. Name the product and the colour as the maker prints them. If two samples only differ in the hand, say that, and say which one you are asking them to trust from memory.
The lighting guess is the whole fight
Most finish regrets are an unstated premise about light or wear. Put it on its own line: you assumed the west window is unshaded after three; you assumed they still want the dark grout; you assumed the sample they photographed is the same dye lot. A client will correct a labelled line. They will not interrupt a paragraph that already sounds decided.
If your assistant inferred a preference from a saved picture, mark it inferred. A picture is a feeling. An order is a commitment.
You release it; they reply without signing up
You approve the send. The note uses names they would recognise. A nickname you keep for the project stays on your contact list; it does not appear in the briefing they read.
They do not need an account. A first send is email and a link. If they already have an activated account, a new thread needs an accepted contact pair. They can reply from the mail. That reply is the finish you order.
If two people share the house, one briefing still goes to one mailbox. Say the other person needs to see the two names. Do not treat one thumbs-up as a household.
When you still need the showroom
If they have not seen the pair in their light, say so and book the look. After they have seen it, send the same two names and the same order date. The trip is for the eye. The briefing is for the purchase.