I did finally get SU permissions through ADB, but I dont recall exactly what I did to get prompted to allow access.
I will try to retrace what I did... believe I had ADB shell running (without su permissions "$"), but I also had terminal emulator running on my phone. I entered the su command on my phone, then I did the same from ADB shell.
Finally the phone prompted me to allow access - accepted - and no problems from that point.
Basically, I just had to keep f'n with it.