I was only able to get it to work with two companion switches. The Lutron series does not work properly with two occupancy sensors. My goal was to get the apt on top and the entry way to have the lights turn on when the tenant or person entering opens the door.

I like the lutron; works really well and turns on only when needed if its truly dark.

This is how its the four way with companions would be wired

_{(source: tyronnephotography.com)}

See the diagram and the description for 4-way.
http://www.lutron.com/TechnicalDocumentLibrary/048435.pdf

In the 2011 version of the National Electrical Code, there was Table 310.15(B)(7). This table was quite handy for determining the service conductor size. In the 2014 version, it looks like they've done away with this table. However, the long code trail that has replaced it, seems to basically say the same thing.

National Electrical Code 2011

Article 310 - Conductors for General Wiring

II. Installation

Typical services (in the US) are 100, 150, or 200 ampere (though 60 is common for older dwellings). Which means you'll be dealing with a possible range from 4 AWG copper to 2/0 copper (2 AWG al to 4/0 al). Which means you'll want a device that can accommodate conductors from about 0.3 in. diameter to about 0.7 in. diameter, if you want to cover the whole spectrum of possibilities.