I am using the Curtis Youngblood 30% heli blend in my YS 1.10 with an APC 15x10 on a KMP Critical Mass.
As compared to the old 20/20 blend, this 30% has given me that last little bit I needed to be consistently competitive in the Warbird Silver class in our area. Keep in mind, that big round nose on the Sea Fury is being pulled with enough power to make it competitive with the same powerplant in the pointy nosed P-51's that are so prevalent.
I am not peaking this engine to the nth degree to get the max power out of it. And I have not had to move the needle more than 1/4 turn for the last 10 months.
I think it's safe to guess that the Curtis Youngblood 30% heli blend is safe to run.
http://www.rcuvideos.com/item/LB393Z7TWD25JLHY