For anyone interested;
The best way I have found to map Omnisphere controls is to first- Right click on the Omnisphere knob you want to map & choose "Enable Host Automation"
Then when you expand the parameters list in the browser, double click the SAME knob & it will Choose & show the correct controller number in the list.
THEN right click that number & choose "Link to Controller" & tweak your Hardware knob.
If anyone can do this easier, Please let me know.