rounded-box vs. box in text markup

[Emilio Millan]

Hi all. I'm a fairly new user so I may be missing something obvious.

In the following example, is there a way to "snug up" the rounded
boxes over the second note so that they are vertically spaced like the
boxes over the first note?

\version "2.19.80"
{
  f''2^\markup{\box "1"}^\markup{\box "2"}^\markup{\box "3"}
  f''2^\markup{\rounded-box "1"}^\markup{\rounded-box
"2"}^\markup{\rounded-box "3"}
}

I know I can override box-padding to make the rounded boxes smaller,
but I don't know how to change the space between them.

Regards,
Emilio