What a great dad! How many, uhm...gun turrets are you including?
In theory this is my daughter's project - which I hope my son decides to help on ( another long conversation last night on- well - everything really. ) and I am supervising. But yes its tactical significance is hot being overlooked.
But right now is pretty large.. 8x 12 platform with a 7x8 one story structure. Its also up uncomfortably high for my parental comfort ( 15 feet) but then I think back to my childhood and realize the ones I played in where higher and far less sturdy, and that is what railings and walls are for.