Hi Viking,
I tend to use Purchasing Power Parity (PPP) as an overlay to my US stock purchases. Our currency here in Australia has certainly been manic over the last few years. In order to keep this in perpsective I divide my fair value of BRK, FFH and ORH currently by 0.80/0.69 (PPP) to get a currency adjusted valuation. On this basis I figure that I have approximately 16% more purchasing power so my maths work something like this based on what I figure is IV
BRK IV = US120000 est from JKish's intrinsivalutor, BRK Price = US82500 (based on 30 b's) -> 82500/(120000*1.16) So my currency adjusted IV is 59%
FFH IV =1.4 x 255 = US357 FFH price = US242 ->242/(357*1.16) = 58%
ORH IV = 1.4 x 43.8 = US61.32 ORH price = 42.3 -> 42.3/(61.32 * 1.16) = 59.5%
PPP is a very course metric but ultimately seems to at least be a long run anchor point on currency movements.
The usual caveats apply in that you need to be mindful of "printing presses" and the shortcomings of using basic IV measures such as multliples of book value and the intrinsivaluator.
Cheers
nwoodman