yep. theres forum on the site you order from, that has some info on this.
you can pre prepare them but they have to be consumed within 12 hours, and need to be kept cold/refridgerated, so he'd take them in a cool pack or something while travelling.

I think metamucil is fine, it has sugar in it though which I'm guessing is why its not one of the ones they recommend. I've got benefiber just cos it was on special.