Time syncing

I’m running whonix gateway and Linux system as workstation. Both gateway and workstation clocks in vbox is set to utc.
Gateway clock is in good range, because tor is working, but workstation (not whonix-workstation) time is out of range, i mean very different from host and gateway clocks. The question is, how important that is to anonymity? Does correct clock is important only in gateway or in workstation also?

To my best knowledge this is important. See also:

In this case I think you’re vulnerable to the “Linking all sessions to the same pseudonym” attack.

If i turned javascript off, can they still see my system time ?

Probably yes. It’s also leaked by SSL.

One example:

But others are probably affected as well.

I see now, this is really important. Does it enough to adjust my workstation clock by hand or i need some script like in whonix workstation ? How precise system clock should be (in minutes, in seconds, in milliseconds) ?

For example, when using TBB, Tor exit nodes, the ISP's of Tor exit nodes and destination servers can see client's clock.

Just to be sure, tor entry guards and middle relays, can’t see my clock, right ?

Doing manually is fine. Will just be troublesome to never f orget doing it. Also also not connecting to the internet before timesync is done will be a challenge.

Just to be sure, tor entry guards and middle relays, can’t see my clock, right ?
If they could, then it would be Whonix-Gateway's clock. They fixed the leak after I reported it. See: https://trac.torproject.org/projects/tor/ticket/7277 But the fix won't be available before Tor 0.2.5, I think.
How precise system clock should be (in minutes, in seconds, in milliseconds) ?
One important thing is being different from your host's clock. If it was as accurate as your guest operating system's default mechanism, that's be optimal.

For milliseconds see: