Grammar structure of the various stages of IE

Hi, Glen:

 

You keep referring to various stages of IE, such as Pre-IE ( IndoTyrrhenian?), Early PIE, Middle PIE, early Late IE, Late PIE.  Forgive me if you've done this already a long time ago, but I was wondering if you could provide grammar overviews for Early, Middle, and Late PIE as you did for Proto-Stepp and IndoTyrrhenian.  I've looked over your website, and you have phonology info and info about numerals for the three stages, but no specific grammar information.

 

I've seen many references on the web about PIE having gone through an ergative stage and possibly an active stage (in what order, active > ergative, or ergative > active?), but when would these have occurred?  Here are some references that I've found.  I haven't read them myself, though.

 

K. H. Schmidt. "Active and Ergative Stages of Pre-IE." Ergativity 1979: 333-345.