Well, been on a 4dB profile for a couple of days and it's solid. Attainable up from 47 to 53 -- so each 3dB drop gave a rise of about 3Mbit.
ESs are at about 20-odd per day, and SES are between zero and 10 per day. So I imagine its likely that the line will drop to a 3dB Target SNRM soon.
If that gets me to 57Mbit attainable, I'll be very happy. 57Mbit is what my line got when FTTC was first enabled back in 2012. Undoing the speed loss due to crosstalkers would be nice!