If I remember correctly, the "trim" selection on the remote for the 950 will activate the same level settings but without the 950's noise generator. You can adjust to your test DVD using "trim."

As to which is better, even slight differences in the content of the noise will cause you to hear different levels, probably because of system and listening environment issues. From here, I can't know which noise will work better for you. In theory, I would go with the DVD test because that signal passes through the whole system, not just at some point beginning part-way through. You may have to carefully adjust with the 950 noise, followed by listening to normal audio material for a while, then adjust based on the DVD test noise and repeat the same normal material listening check. After all, how the actual listening material sounds to you is the bottom line.