The button events should not be that slow, seems like some sort of z-wave mesh issue honestly.
For the associations, this tool will let you do multi channel:
[BETA] ZWave Tweaker port from ST
The second post has a brief guide on how to do it. Its a very rough port of a tool from Smart Things but it gets the job done.
I think someone else has a tool out there with a more polished interface, I forgot if it does multichannel though. Going to see if I can find it. FOUND IT but I don't think this one can do multi-channel so you are stuck with my Tweaker tool:
Need direct ASSOCIATIONS - #3 by MrFarmer
