Sync issue - audio & Midi lined up, but bars are wrong

Hi,
 
I've been working on this for days, and keep going back to the drawing board!  I have a finished album cut that I'm now trying to put horn parts to.  I want to take the original MIDI piano part, edit it, and use it as a base for the horns.  The MIDI and audio file lines up, but the bars and measures are wrong.
 
So, I used "Fit To Time" by laying down a reference MIDI track.  Result?  The bars look right as far as the audio goes, but now the MIDI track is WAAAYYYY too slow.  Brought it back up to the original speed, now the MIDI track is racing.  Brought it back down, too slow.  The end result was so botched that I started over again - twice.
 
So, I'm going to start editing the piano MIDI track again, but before I do, I'd like everything to line up.  This way I can give the guys charts that will, to a degree at least, make some kind of sense.
 
How do I do this?
 
Thanks!
 
- Russ

Thanks for the reply, Dan.
 
There aren't any plug-ins, though.  In fact, I ended  up taking the mastered track to use as reference, then lining up the MIDI track to it, at a default of 120 (which is what the original recording was done at, much to my despair.)  The actual tempo is about 66.
 
So, here's the question (I think) - is there a way to get the bars to line up with a reference track WITHOUT having the MIDI part change - so it will stay exactly as it is in terms of timing?  Or do I need to come up with some complex mathematical formula and use the "Length" command, then spend hours tweaking it to individual bars?
 
Maybe I should consider having the horns switch to kazoos for this number...
 
- Russ

Yes, I had tried that but it made everything go wacky as the midi track was now too slow.  So, here's what I did (finishing up now):
 
Put in a MIDI reference track, one beat per quarter note.
Fit to Improvisation, which messed up the MIDI timing.
Made a note of the (roughly) average tempo, which was about 70 bpm
Put it back to 120.
Set tempo at bar one to 70.
Using the length command, I changed the start times on the MIDI track to 70%.  I used some convoluted formula to figure it out, which was completely wrong (hey, math was never my strong point) and said to use 30%.  I realized it was about half too slow, so I tried 70% and it was pretty darn close.
Tweaked the tempo map by playing the audio track and used Shift-M (set Measure/Beat at Now) to make adjustments at various measures.
Made prolific use of the scissors tool to cut the MIDI track and line things back up again, roughly every three or four measures.
It's now at the correct tempo all the way around, and more importantly, I can make the horn charts and they'll look right on the printout.  BTW - I'm exporting the MIDI, opening it up in Realband, and printing it from there because it looks MUCH better than the Sonar notation.
 
Thanks for the help and the suggestions!
 
- Russ