Yes, Scouts, not so much ;-)
Hindsight I know, but compression stuff sacks would have shrunk their sleeping bag size.
As rule of thumb we tell all our crew members that their packs must be large enough so with all their personal gear they still have at least another cubic foot of space for some crew gear and all the food, and that may add another 10 pounds of weight.
But it is hard to convince novices of how much stuff there will be. Just like how hard humping too heavy packs up and down steep mountains in thin air.
Training, training and more training is the best way to convince novices the importance of packing smart.
“Philmont should be enjoyed, not endured.” moonshine