The way I do this is, if possible, use a name where the last
letter isn't repeated elsewhere. For ex. Harry Williams, then make
S the shortcut. You were on the right track, but it wouldn't work
because there are two H's and when the first H (Harry) is entered
it tries to continue but comes back with the failure because the
use has to enter Harry Smith.
I don't know if there is any other way to do this or not.
This is the best solution I've seen though.