I voted for "More of..."
My choice would be more visiting military.
One of the visiting officers (a grown up Army brat, I think) told the brothers that he had heard some astonishing things from the Kids. How about a chapter when a soldier or officer repeats this line to the readers (and his fellow military), adding "and then I SAW some astonishing things", going on to describe one of the weekend encounters from the soldiers' point of view.
By now, the Kids have some experience, so it might be time for one of the earlier visiting Marine groups to return at their own request, knowing full well WHO they will be dealing with, but not what new tricks the Kids will have waiting! I like it when the Kids and the military earn each others' respect, and treat everyone civily as soldiers and men.
Could Jap have a rematch on the firing range where, after explaining what particular gun he usually shoots, lets the other guy use Bert? The 2 shooters would explain to others that this time, they just want to know for themselves who is better, but they do have some personal money at risk, just to prevent either from "letting" the other win.