Controllling repeat volta text

[Stan Mulder]

I have a jazz piece with a repeating solo section. The number of times it
repeats is indefinite. How do I notate this and then have a final measure
which is the "last time" through that section.

I played with the \set Score.repeatCommands commands, but I cannot quite get
it right.

Below is what I have so far. It's almost correct except that the repeat text
says "1." and "2." for the 1st repeat and last time repeat. Do I just
control text or is there a specific command to control this.

\repeat "volta" 2 {
  s1*8
  s1*8
  s1*8
  s1*7
}
\alternative {
  { s1 } % repeat as many times as necessary. Maybe "1 thru 99"
  { s1 } % "last time" ending
}