From the x2go page, get the client for Windows (or Mac).
There's an unstated (I think) requisite -- the Microsoft Visual C Runtime. If some other install hasn't already taken care of this, find the download at microsoft.com. The x2go client was compiled 32-bit, so you need the x86 version, even for 64-bit Windows.
Install, and run for the first time. Have speakers and mic, or else put up with ...
From the menu, Session, New Session.
If you say your network is fast, then screen update will be favoured, and that is at the expense of keyboard and mouse response. ADSL is probably right.
Expect no pleasure from youtube.
For Compression Method and Image quality, the large choice suggests there is no good answer. You might try 16m-jpeg and 5, or leave things alone.
1600x960 will fit within 1920x1280.
Here you might turn off audio input if you don't have a mic, or turn off sound altogether. Not much loss.
Same problem, new context. See above.
x2go client requires XQuartz, and works just about the same as above.
(Well, no it doesn't. For MacOS 10.14, the release client fails; use the nightly build. Expect the situation to change soon. Dec 6, 2008)
But if you have XQuartz, and you can do without the upline window manager, you might be better off running X over ssh.
ssh -CYf firstname.lastname@example.org xterm
A.E. Oct 2018