Len,

Are you sure the vibration is a tracking problem anyway?

It might be

1) blade balance rather than track - so add a piece of tape to one blade and if vibration gets worse switch it to the other, keep adding tape until the vibbration is minimised.

2) non-aligned bearing blocks. This one really worked for me after someone on Ezone suggested it. Loosen the three bolts that hold each bearing block a little so there is some "give". With the heli held down spin the rotor up to speed (but not so much as it actually lifts). Now stop the rotor and tighten the bolts. This got rid of a major vibration in my Corona as it makes the rotational axis of the two blocks exactly perpendicular and prevents the shaft binding.

Cliff