Circled rehearsal mark size

[Vaylor Trucks]

Take a look at the following:

        \set Score.markFormatter = #format-mark-numbers
        s8
        \mark #9 s8
        \mark #10 s4
        \set Score.markFormatter = #format-mark-circle-numbers
        \mark #9 s8
        \mark #10 s4

As you can see, when using circled numbered rehearsal marks the size of the 
circle must, by necessity, go up when you enter double digits.  Is there any 
way to make the circle for rehearsal marks 1-9 the same size as the circle 
for rehearsal marks 10-99 without increasing the size of the text?  In other
words, what I would like to do is have the same size "9" centered in a larger
circle so that when "10" comes around the mark isn't such a noticeably larger
mark.