Thanks guys. As I said earlier, I've noticed a good increase in power. I did finally get my tach working, and was able to get a direct comparison today. Using the 15 % byrons fuel, I was turning somewhere around 10500 with a 12 x 5 mas prop. In comparison, I was getting over 11500 with the 30%. Not much increase, but 11500 is pushing the mechanical limits of this engine. I may notice an even larger margin of difference when I go to a higher pitch prop. I'm thinking maybe a 12 x7 or something like that. I have some 12 x 8, but I still think they are too much. I will, however, try them again using the 30%. Another thing I noticed today. The other day when I first used the 30% I had to richen it up quite a bit. I attributed it to the cold weather. However, today when I went back to the 15% (for comparison purposes), I had to lean it up quite a bit (after having already flown on 30% with no problems at all). So, running more nitro does require me to open the carb up quite a bit. Almost a 1/2 turn! I'm attributing that to more power, more RPM's, more need for fuel!
So, there is the verdict. A 100+ RPM difference between 15% and 30% on the Saito .56. I shall try the same experiment with my Saito 100 someday and report on those differences as well!