a POV picture of their last studio session (was another kit back then). looks a little better from his angle!
Are people serious suggesting turning down a recording project because the drummer plays ride on the left :-O
This is the way he plays. So be it.
Holding band meetings etc and trying to get him to change the way he plays will loose you the project.
Forget about spot micing and trying to change the pan. It won't work.
Treat the overheads as a single stereo source rather than individual cymbals.
I would go with ORTF over the snare and pan them 9 o'clock and 3 o'clock.
Try and get him to use the crash on his right as much as possible and suggest he "rides" that crash in place of the ride for some songs (choruses)
Once you get to the mix it will be fine.
Maybe not as wide as a hard panned stereo pair but you will have strong centre energy for the kit.
Mickrich's plan could lead to an off center snare in the OH, mind.
ORTF over the snare would keep snare centre.
That's the whole reason I suggested it, so you could reduce the stereo image of the overheads without centre shifting the snare.
I'm a dumbass, I thought you suggested to only pan the cymbal heavier side more towards center, sorry!
I think it's cool to have unusual stuff to work on, my worry with that setup would only be, that it could get boring and one sided to have mostly all the crashes on one side.
That really depends on how he used them though, if he almost always used the right cymbal as the first hit then it's not as bad.
But still, most of the lead hands will be on the left side in most cases, I assume.
Maybe trying out some percussion (shaker etc) would be nice to fill out the space on the other side, in case you notice that it gets a bit one sided after a while.