Choosing the Name of the Hero of My New Novel

Yesterday I chose the name Harry Royston for the hero of my new Regency novel Tuesday's Child a follow on novel from Sunday's Child and Monday's Child. However, the heroine of Tuesday''s Child is Harriet, who had a walk on, but important part, in Monday's Child. I think Harry and Harriet might be confusing, but most people would address Harry as Royston, so maybe I'll choose it.

Other possibilities are for a strong name for a strong hero and a nickname which implies fun and light heartedness are:

Alexander aka Alex, but does Alex imply fun and light-heartedness?

Christopher aka Kit, but the name fell into disfavour in the 19th century.

Dominic aka Nic; I think Nic implies a devil may care attitude which might be amusing.

Of course the surname will be as important as the Christian name.