This testing peace is first section of right wing from 3D printed hand launch plane KRAGA Tere. If you are able to print this part you should be able to print whole plane.
KRAGA Tere is 70 cm big hand launch glider without remote control which is printed on 3D printer and reinforced with carbon spars.
More info at https://www.3DprintedRCplanes.com/tere
Video of assembled plane: https://www.youtube.com/watch?v=vuwRKqikM88
The file is available also here: https://3dprintedrcplanes.com/download_test/tere/
The part has to be printed as shell - 0% infill and no horizontal surfaces (thickness of the shell is one layer). Only this way you can achieve required weight of the plane.
Nozzle: 0.4 mm Layer thickness: 0.19 mm Rafts: yes
Use the default orientation and whatever printing material.
Your result should weight 6 g. The wall of the shell should be printed by one pass of printing head so that the shell is very thin. You should be able to fit carbon tube with diameter of 2 mm into spar leading holes (bottom side of the part).
I recommend to try to cover testing part with covering film to test if material of your choice will not deform from ironing heat and if covering film will stick on it (I tested many materials with multiple covering film brands without issues but it can theoretically happen).