For both options ยท Shared later
What he keeps private for now
This is the full list of what he keeps private for now, and when he shares it with you. There is nothing else.
Why he keeps these private
Many people can read this website, not only you. He has business partners, clients and family who did not choose to be part of this. A name on a public website stays there for years.
Nothing on this list stays hidden from you. He keeps it private until there is a reason to trust you, which is the same test you are using for him. The difference is that he goes first. By step 4, he has given you his name and his medical records. You have given him a letter.
What is not private
This website already shows his age, his height, his health and fertility, and his education and work in general terms. It also shows the languages he speaks, and the details of both options. Everything has a date, and you can read it all before you give him anything.
What is private is the short list above. You get every item on it before you make any important decision. At no point does he know something important about the plan that you do not.
You do not need to be as careful as he is
Some women write with their full name in the first letter. Others use an email address that says nothing about them. Both are fine, and neither counts for or against you.
If you prefer to stay anonymous until he has told you who he is, just say so. He will respect it and not ask again.