Seems a massive amount of weight MY zona zenith(2.2kg frame) was at it's heaviest only 11.2kg, and that was with a rear echo 07 rim, echo cnc cranks, gigapipe bb and 203 BB7 Try weighing again?
Kits are around £20 here, and im sure an engineering firm would be able to help. The ship building industry i know is big out there, and helicoils are often used in marine applications.