fuel lines/turbo actuator pipe

[hongkongstuey]

are these the same pipe type, only asking cos they look the same and i want to replace the actuator vacuum pipe because its a bit tight on its run round to where it plugs into the module (n75?) after replacing my fuel temp sensor i noticed the pipe going to the first injector was very perished, on the verge of crumbling to nothing, but not leaking. so here are my questions

what is inside diameter of the fuel pipes (from fuel pump to first injector and bridges between each one, afn engine) and do they need bonding on (no clips to hold them on)?
same for the vaccum pipe from actuator top to module, going to replace them with silicone pipes. should only need 2m or so and samco do every size under the sun.

any help would be much appreciated

edit: the pipes are the fuel return pipes, prone to cracking, ordered some samco hose