Transmission syncros

[Reid, Les C.]

I am considering replacing the syncros in my transmission.  1st gear is
the worst (car must almost be stopped to engage), 2nd gear is bad as
well (have to up the rpm when going above 15mph), 3rd-5th are so-so.  I
have already changed the fluid (no noticeable difference)

Is there anyone out there with BTDT experience that could give me some
pointers?

Is there a way to check if the clutch plate is completely disengaging?
I also hear a rattle when the clutch is held down while stopped.  Think
this is the throw-out bearing.

Clutch/TObearing was replaced 60k ago by previous owner.

I don't post that much, but I really appreciate you guys, especially
Bernie.

Thanks
Les Reid