im buying some silicone hose lengths to do such pipes as the radiator overflow pipes/oil breather pipe Etc basically every blue hose in the photo below of mx5maniac's sexy car (see pic below), however i will be getting YELLOW (no suprise there)

does anyone know what thickness hoses i will need to do all these..
i have found a set with 4mm 6mm and 8mm hoses....and another set has 4mm 6mm and 10mm hoses
your help is always appreciated
Cheers
Ajay