Wheeling R wheels on an X: sprockets?

I'll pick up a set of Wheeling R wheels in May, just over 2 weeks before a 3 day ADV 'enduro' event
(from advrider: Roaming Rally: Ontario Ride 2012: http://www.advrider.com/forums/showthread.php?t=692873 )

I only have to weeks after getting the wheels before the ride, so I need to get the sprockets sizes right.

Ideally I want a front sprocket size that works with both the X rear wheel and R rear wheel.
I like the stock X gearing (stock size front & rear sprockets), but I don't mind getting a different X rear sprocket size if I need to change to a different front sprocket to get decent R wheel offroad gearing.

So is there a front sprocket size that works with X & R rear sprockets?
(I'll have one rear sprocket for each wheel, so I don't mind different sizes for the X & R)

Of course if I use different rear sprocket sizes, I need to be able to change wheels without changing the chain.
Would one chain length work with 2 diffrent rear sprocket sizes? (enough adjustability within wheel chain-slack adjusters?)

Do you X owners who regularly swap between stock X wheels and Wheeling R wheels bother adjusting front suspension height?
Or is the front tire height difference about the same for the R vs X wheel/tire?

Sorry moderators if this belongs in the 'Sprockets and Chains' section, or maybe the 'Wheels' section, but I thought the questions are specific only to X owners...

If you go with a 112link chain, you could run 13/48 on the R rims and then 13/42 on the X rims. Should be good.