The GAC is usually given for a party of up to 6 people (5 plus the person with a disability that it is issued to). The CM may issue the GAC for a larger group, but it is up to the indivual attractions to determine the largest size of party. There are some attractions - particularly in Fantasyland, where the waiting area is very small and they may limit your party. If you still have your old GAC, it would be useful to bring that to show the CMS. If you can't - just be prepared to explain what needs he has.
There is a whole section of information about GACs in the disABILITIES FAQs thread that should be helpful for you. Exactly how the GAC is handled depends on what it says, which is based on the needs the person has.
NOTE TO POSTERS: Please don't respond with the 'type' of GAC to ask for or the wording.
It also depends on things like how busy the attraction is, the space available and the staffing at that attraction. Because of that, the same attraction may be handled differently at different times -we have sometimes been directed to the Fastpass line, and later duing the same trip with the same GAC, we've been given a slip of paper with a return time written on it. Other people have reported the same experience.
For the most consistent handling at the attraction, getting Fastpasses is the best. With a Fastpass, you know that from the time you get into line, you will be getting on the attraction in usually less than 10 minutes.
Rather than taking your whole party to the attraction to get Fastpasses, it works well to send one or 2 people ahead to get Fastpasses. You don't all have to be present - the person getting the Fastpasses just need to have all of your park passes to put into the machine.
It's also helpful to know when different parks and parts of the the park are busy. Knowing that can make the difference between a standby line that is an hour long and one that is walk right on. That can be even more important than having a GAC because the GAC only helps in line, and if the park is busy, you still have to contend with the crowds walking from place to place and lines in places like restaurants and restrooms.
A good example is Spaceship Earth at Epcot - in the morning, the lines are very long. By late afternoon, you can walk right on. The same thing happens at AK; many attractions like Kali River Rapids and the Safari have long lines early in the day because people hit that park early and many leave by 3. We've been on both many times in a row in the afternoon because the standby line is just walking right on. Even during busy times like Spring break, it's possible to get on all the attractions in Fantasyland before noon with very short waits (like 5 minutes) if you can get to MK at opening.
Guidebooks and services like Tour Guide Mike (a Theme Parks Board sponsor) can be helpful with figuring this out.
