My headphone and 2 channel rigs are almost identical. Except for the Parasound A21+ amp on the speakers and the CODA #8 amp on the headphones (1 preamp to both amps). Long term the Parasound will be upgraded with another CODA amp. I will also get the same speaker wire for the headphones and the speaker. The headphone currently has my best speaker cables.
I cannot use a bright DAC on my headphones, there is little room for error with the headphones. If it works well on the headphones, it will also work on the speakers, this is not always the case in the opposite direction. I try to maximize my system (DAC, cables) via the headphones.