Yep, that obvious!

Reading the fitting instructions it is suggested that the tank is set to a 20 degree incline and the brass nipples are facing up, but the wording is not 100%, have slightly less space to play with on the top set up but enough to achieve the desired result.

When I looked at other threads regarding this, and the picture you posted for that matter the tank is mounted vertically, not at the 20 degree incline, so my interpretation lead me to thinking it may not be that critical.

Will post some updates tomorrow as I know Al is back from Top Gun.

Marc.