Can I suggest that basically all correspondence between individuals in the EPICS v4 goes through the epics-pvdata-devel mailing list?
My experience with W3C showed me how useful that is:
1) All correspondence is archived
2) Each correspondence available on the web 
3) Any correspondence can be individually referenced in follow-up emails, eg like this, "At some point I think we're going to need to seriously review Michael's pvDataCPP thoughts "
4) Sending stuff to everyone shows us all where the effort is going.
5) Sending things to everyone and to a public list - watched my managers and other EPICS people - forces one to be precis, avoid hyperbole and bs.
Ok, so just my opinion