From your terminal on the mac you will be connecting from. I was missing this part before and therefore it was not working.
sudo defaults write com.apple.ScreenSharing skipLocalAddressCheck -boolean YES
From client mac connect to linux server and map your port 6900 to its 5900. Really you could use any ports you want just make sure that you use them in the next command too.
ssh -p 22 -L 6900:127.0.0.1:5900 user@linuxserver
From linux server connect to target mac that you want to view mapping its port 5900 to the mac port 5900. The first port is whatever the second port was above. The last 5900 needs to be that as the mac runs its dekstop screen sharing over port 5900.
ssh -L 5900:127.0.0.1:5900 user@targetmac
From there mac you want to view the other mac on, open the finder's menu and select go - connect to server.
enter address as your localhost and whatever port you chose as the first one in the first ssh command
vnc://127.0.0.1:6900
hit connect
login with the account for the targetmac
from view menu select the display you want to view. From there you should see and be able to control the target mac.
I somehow feel like they are giving it away free for some subversive guinea pig bug testing on suckers.
That looks like a video game. I don't remember their house being that impressive... is it really?! Did they bring in extra trees from somewhere like that one bloke on pearl who brought in plastic flowers overnight just before the garden walk?