need expert on oils
 

What do you consider the best oil?
I have been using Ucon LB625 for the last couple of years but I have ran out and can't seem to find any available.
I run model hydro boats and the mix I use is 50% nitro 18% synthetic 2% castor.The engines run from 23,000 to 40,000 RPM depending on engine size.
As you can see we are extremly hard on engines.
Lb625 is a gycol based oil, I don't know about Klotz but I have had problems in the past with it.
One person recommended ester oil used in refrigeration.Cost about 8.00 a pint.which make for one expensive gallon of fuel.I will be gratful for any help that you may offer.
Thanks
Jerry