That's a great result. Interesting that the 4% nitro did not give any RPM boost, but the change in oil meant you had 4% more fuel in the second mixture which can be a boost of it's own. Hmmm. The E-85 runs great in my leaf blower, and I use a 3% castor mix. It smells nice, and if I get into a corner where I smell the exhaust it reminds me of when I was a kid playing with Cox fuel and some cranky .049's.
-Tom