Tubing for pitot/static system

Looking to tie into pitot/static system on '67 Citabria. The pitot line runs directly to the back of the air speed indicator. The static line runs to air speed indicator and then Ts off to altimeter. I have the factory service manual and have a drawing of the back of the panel. I also took a look with bore scope and it looks just like manual. I have a Garmin G5 that need pitot and static comes female 1/8 x 27 NPT. What size is the tubing and what is it. It is metal, looks like it might be aluminum of plated. What kind of fitting, compression ring/flair?

That would be the kind your A&P uses as this is not something that an owner is allowed to perform. The G5 install uses an STC which means that a 337 needs to be completed by an IA.