Hmm I dunno about the G major being as there is no F in G major. And as for the F lydian for chorus that may be but i dont know. I play D mixolydian throughout the whole song and throw the F in there for the Chorus. If you want D mixolydian go to
www.wholenote.com then up top click on Basics then down below youll see a box that says scale finder. I tabbed out the first scale box shown there for ya so you can see how the dots represent the notes.
E|--------------------------------------------2--3--5
B|-------------------------------------*3*-5-------
G|----------------------------2--4--5---------------
D|-------------------2--4--5-----------------------
A|---------2--3-*5*--------------------------------E|2--3--5------------------------------------------
The notes with asterisks are your Root notes for the scale which in this case would be D.
And there ya have it. Good luck