Bob,
just go back to the standard settings for the G-26.
a. Low-Speed Needle: 1 1/8
b. High-Speed Needle: 1 3/8

The 1/4 open from max rpm is only on the high speed needle. Try the standard settings and let me know how you do. You could even start at 1 1/4 and 1 1/2 to stay a bit rich but the stock settings work fine. How did you work out max rpm?
What plane do you have it on. I use a 17x8 Xoar prop and have a huge amount of success on it. i las had it on a 16.5 pound Giant Thunderbolt and it flew it well.

good luck
Paul