I can't claim expertise on this topic, but I have spent enough time tweaking reeds on enough instruments that I may be able to add something..
Clarification questions: is this english, anglo, hybrid, etc?
Valves: The no valves thing raises a red flag in my mind. If other reeds behaving well at similar pitch are valved, but the opposing reeds on the inefficient buttons are not valved, that could be a factor. My understanding (and would love for others to fill me in if this is an incomplete understanding) is that the highest reeds don't need valves because they are unlike