You're not being overly picky are you?...
Even where you skooch yer' butt will make the tree tilt a tiny bit right or left...
... but, in the old days, I used to tweak the forks on my dirt bike all the time...
I just pinch the wheel between my legs and pull the bars to get it back...
You might try, raising the front end,.. loosening all the pinch bolts and letting the forks settle... make sure the top of the tubes are at even height... then tighten everything down...
If that don't come out straight,.. you might have a slightly bent tube...
If it ain't binding,.. just eyeball and twist with yer' buddy like you were doing to get it as close as possible...
... or buy new tubes... but I wouldn't..
Close is good enough for me...
...
PS... gonna' have to check out what r.f. just said... I never noticed that...
...
PSS... if you have a fork brace,.. they can tweak the tubes if not installed carefully...