2c-b following MDMA is a personal favorite of mine (although I always throw 80ug LSD into the mix an hour before the MDMA).

It sounds like maybe you waited a little too long before taking the 2c-b. My greatest experiences in the Nexus have been when I took the 2c-b maybe halfway through the MDMA, definitely no more than halfway (that's about 2-2.5 hours after ingest for me). I find that 2c-b integrates a much more "practical", grounded type of mental state into my usually idealistic MDMA thoughts. I find it produces a wildly different but equally valuable kind of insight that I am able to take much more away from. Additionally, I really dig the enhanced sense of psychedelia that the 2c-b adds to the otherwise not-so-psychedelic MDMA experience. I would take a rest for a month and then give a different timing a try!