This company is worth talking too -
http://www.opieoils.co.uk/
The guys that run it seem to know a hell of a lot about oil, are partially independant and VERY enthusiastic (a rare combination of good qualities in the motorsport world). They answer oil related questions on another forum but I am not if it would be 'PC' to give the details here.
I suppose one viewpoint would not to be to find an equivelent oil for a given application, but to find the BEST one for that application.