You could take it to 155 degrees I would recommend. I run 160 or more on most of my other engines, but I rev them higher than the Ryobi is safe to go. It's good to raise the transfers about the same amount you raise the exhaust, but it's a little tough to do without a mill. A small mill bit in a dremel or die grinder will do it, but it sure takes a steady and sure hand... Try to maintain whatever angle, both upwards and sideways that the transfers have originally.

AV8TOR