feedback/discussion now that public comment period is over

Where can I send comments about or have discussion regarding the OData v4 spec now that the public comment period is over?

I would like to know if the $select and $expand system query options are allowed on insert entity requests to limit or expand the data that is returned (when it is requested via a PREFER header that data be returned).  A section that clearly indicates what system query options are allowed on the various combinations of URL type and HTTP method would be helpful (unless it exists already and I just missed it).

Ron