Like many, many others I built various Scientific kits. With a young person's impatience, I sanded the wings just enough to get the mill marks off, never thought of additional fuselage hollowing...heck it was already hollow, and yes, used the gauze around the firewall. A few terrible coats of dope and she was ready to fly!
Mine became more complicated when I bought a NEW Space Bug Junior and had to drill a 1/4" hole for the intake, and also make sure air could get into the fuselage. Of course the old OK Cub required me to bury a small metal fuel tank in the fuselage so maybe it was a wash.
Those planes were probably heavy enough they could not loop...but then, neither could I. :-)
George