Me, personally, I don't think there's a problem with that. May as well set it where you want your gain.
Also, if you don't compete or run lots of 0 db test tones through, you could use a -3 db test tone and multiply your target voltage by 1.41 to maxmize your power output. Music is between -5.6 and lower (ususally) and so
Sqrt(Watt x impedance)1.41= setting voltage
1.41 is equal to a 3 db gain, so it would be like you're using a -6 db test tone.
This what I do and it works great.