If the tail/rear of the fuselage is hollow, I guess you could shoot some expanding foam in there to firm things up a little and it'll be negligible weight gain. It'll help keep it afloat in case of a crack or hole.

Just a thought, I haven't even bought mine yet. After the retract gear arrived I read about the quality problem so I cancelled my Tower order for the first run kits, I'll get mine after the first of the year.

Don