I have searched a little on this so don't flame me for not doing so..
Anyway I just recently changed my plugs and I used the NGK laser platinium bought from Advance Auto. They told me the gap was .44 and they were set at .39 when I took them out of the box.
The plugs that came out of it were Denso PK22PR-L11S and they were gapped at .44
Now this might be my imagination but I think I may feel it running a little rough at idle so I was wondering if I should have left them set at .39

 

the factory plugs will come on the tighter end of the Honda spec as the gap will open up as you put miles on them due to erosion of the center electrode. The Densos were on the wider end of the spec. I wouldn't worry about the gap if you plan on running them for a few years as it will open up from there, if you are the type to pull and replace the plugs every couple of years you can run them a bit wider. I wouldn't think it would affect the idle, but who knows. I'd run them for a bit and see how it goes.

 

I don't know off hand but I think .39 is close to spec. I would use them as is.

 

yup .039-.043 inches is the spec range, with .051 inches the service limit.

 

I think I will pull them and return them and order the Densos nothing is wrong with the way it is running except it feels like a slight vibration as it idles, it may have been like that before I changed them but I want to try it just to make sure.