Basically the site also states that everyone is right:
First pressed, filtered and then degummed to give you the unique lubricating properties of castor without excessive buildup and carbon. CleanCastor™ is not chemically extracted, giving it superior anti-scuffing properties under high bearing loads. The additives in our Omega and Sidewinder fuels combine with the CleanCastor™ to adhere more strongly to metals than ordinary castors.
So the Omega fuel does contain castor oil, but a modified version and, if you believe what they say, therefor lubricates better than 'ordinary castors'.. I was referring to ordinairy castor oil.
Anyways, this thread was not about the best break-in oil (sorry my bad). No-one got any further comments on the difference between 5 or 15% nitro, or the necessity to use 15%?