Electronic Boost Controller location and vacuum hose lengths

When setting up an EBC are there any ideal locations for the solenoid? I remember reading something like the vacuum hose should be as short as possible between the solenoid and the manifold, or the solenoid and the controller but I can't remember which or where I read it. Does anyone have any input on this?

Secondly, depending on the answer to the question above im trying to work out how much 4mm and 6mm hose I need. I am running the stock recirc valves, turbos and wastegates with an aftermarket EBC.

Thirdly, with regard to 'T-ing' of vacuum line for use by different items such as multiple boost gauges and boost controllers etc is there any problem with accuracy running several items from one feed inside the cabin?

Cheerz guys