QT upgrade after OS downgrade to 10.4.8

FCP would not capture after upgrading to 10.4.9.
I did the archive/reinstall to 10.4.8, now FCP seems to work but garageband and IDVD are requesting at least QT 7.0.4. Unfortunately, my trust in Apple OS upgrades is gone.

Which version of Quicktime is "safe" to upgrade to for users of FCP 4.5HD?
I know there have been issues.

Specs: Pre-intel IMAC 1.8
Current OS 10.4.8
FCP 4.5 HD
QT needs to be upgraded now to at least 7.0.4 as per. notes above.

Thank you!