The part about excessive curling is not evident in the rolls I have used (30ish). What I use is ID-11 @ 1-1 and the water I use here in Vancouver is quite soft so that might what is helping the flatness of the negs. As for the "scum" that is reported I just do a longer than normal with more agitations through the wash. One of great things about it it is a great practice film to use in between my usual Neopan Acros film and I did have several rolls that were printable. And with "free" shipping I always have this film in my freezer.
1-Shanghai GP3 1-1 ID-11007.jpg