Some questions about masternode.

I just finished yesterday setting up a masternode with the cold wallet instructions (using VPS and windows machine)

-How long does it take before I see the first income? Will I see this on the windows wallet?
-can I leave the gui wallet on windows closed while VPS remains on? Does this affect income?
-do I have to enter a reward address when adding the masternode? Or can I leave this empty.

Thanks :-)