best air system set-up

Hello All, I'm in the process of setting up my shop for building hotrods. I have a 7hp 80 gallon 15 CFM @ 90 PSI 175 max PSI compressor, and was not sure what size pipe to run. I looked at the Devilbiss desiccant air filter system and it has 3/4" fittings. I also looked at the Eastwood...