Ok reedmakers…lets hear your tricks for bringing G1 a few cents lower!
Ready…GO! 
You can always tape the hole.
My reeds have this problem too, along with a sharp F#. 
sometimes (in this case), it’s a wee bit of tape… or make an entirely new reed with different dimensions (as I know it plays a good G1 with a different style reed). Taping & making music beats the hell out of making dust!
I wonder if it could be the chanter, not the reed?
Those of us who started out on GHB are pretty comfortable with tape. Nice thing about tape is it can be moved during a gig as the chanter changes.
After considerable non-scientific back and forth…and yet more time wasted (or not?), I THINK that the width of the reed has a small but significant affect in evening out the disparity between the pitch of G1 and g2. PERHAPS, Lowering G1 and raising G2, ever so slightly.
I read the eye of the staple has an affect on the G, but I closed a staple eye from 1.6 to 1.48mm and there was absolutely no affect whatsoever on the Gs. So, I’m letting that one go… especially since I’ve had corroboration re: such w. another reed maker who said before my endeavor, “well… i haven’t noticed the eye making any difference to the G.” Well, I concur (today at least).
More news on this later…if there is any…