You should also contact Achim Engels E-mail Address(es):
fts@collectors-edition.de
BTW "FTS" stands for Fokker Team Schorndorf & these guys are where it's at as far as DR-I drawings go. Take a look at his web page too Fokker-Team-Schorndorf -
http://www.fokker-team.de
He has some pics of the grip he built. He also has a complete set of plans for the DR-I.
Mike