It depends on the level the test tone you used.
If you used a 0db test tone, then the gain is set pretty conservatively. You are setting the gain based on the "maximum" sustained signal level. How often does music reach this level? Rarely. It might spend milliseconds at a time at peak levels. Most music is going to spend a majority of it's time at a level much lower than 0db.
It's this reason many people use a test tone with a lower signal level to set their gain. The Autosound 2k guys used to recommend a 3:1 gain ratio for the amplifier to allow a higher average power level at the risk of the brief, transient peaks being possibly slightly clipped (depending on various factors). Their rational was that the period of time the music would spend at a level of 0db was so minimal that the clipping with be neither audible nor damaging to equipment and there would be larger benefits in having he higher average power output. They suggested the use to a test tone that was -10db. This is on the more aggressive side, however, and probably a little much if you listen to a lot of heavily compressed music or music intentionally recorded at high levels.
So you could probably drop down to a -3db or -6db test tone for an initial guesstimate, and then listen and see how it does. If you think it's a little aggressive back it off a little bit.
