Couple things that I would add to Josh's comments;
You are about on target for the attack time, but I would shorten the release time to about 3 to 5 seconds. Keep in mind that the RMS time is already creating an "average" level for 30.5 seconds, so you want the release to be much quicker than the attack. It is like talking loud at a party, and suddenly the music stops, but you don't. It will be about 5 to 10 seconds before average drops enough for the sensor to react, plus the release time. But I would still keep the attack time long, because you don't want the gain to get ahead of the ambient level.
The other is to change the ratio. I have found that a ratio of .5 to .75 works well with a background music system.
Also, I would set the max gain to 6 dB or less. 12 is pretty aggressive, and normally would only be used with paging in an industrial install (a cold storage warehouse, where you have massive chillers coming on and off, also this is where I would leave the ratio at 1 or better).
A word of advice that may not help you with this install (because of a lack of time), but may help others. The first time I used this device, I set up two speakers and a couple of mics and simulated the install in my office. I "played" with this for about 2 weeks, off and on, learning how it worked where I could listen to how the controls impacted performance. Then, when I got on site, it still took about 2 to 3 hours to set the first zone. Once I learned what control settings would work EXACTLY how the customer wanted the system to work for this first zone, it took about 20 minutes for each additional zone. Some minor tweaks over the next couple of days, adjusting the min/max gain etc., and the client was happy.
ALS is a BIG, POWERFUL algorithm, and it will take some learning and time to get it right.
Micah, for this install, you are really going to need to be on floor so you can HEAR how the controls are working. You are on the right track, and I think you are close to having it right, so have patience.
Good luck, and let us know how it goes.
Make it intuitive, never leave them guessing.