VAHEGURU JI KA KHALSA, VAHEGURU JI KI FATEH
A senior Gursikh here advised that the relationship of Naam and Bani are inseparable. When one does Naam Simran, the mind may decide to wander. To keep that under control, he advised that recitation of a pangti in your mind related to Naam Simran and encouraging to continue on with Naam Simran will do two things: One, it will give the mind something to do while you are doing Simran and prevent wandering and two it will further drive Naam Simran to be done, as the pangti will provide the motivation to continue with Simran and provide encouragement.
He also stated that the reverse is true: That when one is listening to Gurbani (and reading, though that may be difficult unless one is a proficient, fluent reader of Gurbani), Simran should be done within your mind for the same reason. The mind may decide to wander, and giving it a task will restrain its wandering and also allow fulfilling hukam of Naam Simran at all times and drive the ras of Gurbani along with the ras of Naam Simran.
There are those Gursikhs who have lots of practice and prem that they can do Gurbani recitation and Naam Simran together - another Gursikh advised that this is not a beginner stage - Gurprasad and abhiaas is required. He referenced a Bibi who did many hours of Gurbani recitation - when he asked when she does all of that Gurbani recitation, she told him confidentially that she has been blessed with the ability to recite Gurbani and internally do Naam Simran at the same time.