I don't think a long hose for the boost gauge will affect the actual reading that much. The boost gauge itself already has some tolerance too.

 

most people I know use a silicone vacuum hose for the segment in the engine bay closest to the engine (where it gets hot) then use a compression fitting to junction with a flexible plastic/nylon tube for the rest of the length. The silicone hose will stretch, and the longer the distance the more it will effect your gauge's accuracy... the stiff nylon tubing doesnt suffer from the same stretching but cannot tolerate the engine temps.

 

The vac line should be as short as possible. I have mine going to the LIM on the firewall side.

 

Where did you connect to the LIM? Do you just T off from one of the line there?

 

Any vac nipple, which everyone is closest. But i have an FC, not an Fd, I don't know if its has as many vacuum nipples.