Maybe I'll be ok...found this on the weber site, although it doesn't mention which weber it is referring to.
Size: Weight is not really an issue as long as the turkey fits in your grill with the lid down to allow for Indirect Cooking (note that turkeys over 24 pounds may not fit under your grill lid). At least one inch clearance between the turkey and lid is ideal. So think structure. A broad, flat bird will fit better than one with a high breast bone. To determine the size of turkey you need to feed a specific number of guests, see our Portion Guide
