I'm sure the helicopter moms would disagree, but I think the "backup meal" is an unnecessary complication and doesn't help a kid learn independence and personal responsibility. Someday he's gonna have to grow up, and part of being a scout is to get moving on learning to be a competent, independent human being.
Just provide the meal you're planning to cook.
If a kid doesn't like it, he can choose to be hungry until the next meal (or to "be prepared" with his own emergency snack). It's not a big deal and it just might help the kid learn a slight modicum of practical humility, not to mention learn to make better decisions next time.
To be completely honest, I was all set to sign up for Woodbadge, right up until I saw my first 15-20 minute long beading ceremony. Watching that, with the song and the fixation of the people involved was enough to make me question my decision. By the time I'd seen my 3rd ceremony (at kid's events no less) and seen the gleeful critter obsession and "I drank the koolaid" attitude of the people involved I was certain I wouldn't voluntarily spend my own time or money on it. Mostly because I don't think I could be around that behavior for 2-3 days straight without contemplating violence.
How does using 24 months make it simpler though? (Do we mean the same thing?) Because using 24 months instead of 2 years it means that if someone just turned 12 on the Friday of a camp-out, they are limited to tenting with someone no older than 13 because anyone who is 14 would have to be more than 24 months older (unless they have the same birthday).
Whereas if you use "2 years" you can just say, "If you are 12, you can't tent with anyone older than 14" and you don't have to worry about specific dates.