Curt's got it- rings are the way to go. Fujis are my favorite apple, and they're my favorite to grill, too. I haven't had much success with tart apples like Granny Smiths or Pink Ladies. They're good for pie 'cause they macerate in sugar for so long. Grilling is counterproductive to successful maceration.
Weber Smokey Joe
18" Weber Kettle
22" Weber clone kettle
Curb-foundling char-broil gasser
WSM: Assembled! First cook: 8/25/06
Fanatical devotion to the Q