Hi
8 cameras setup does not differ much from 6 cameras, i.e. full circle configuration is recommended.
To connect distant cameras to a PC, you need
active USB extension cables like this:
http://www.amazon.com/Extension-Repeater-Compatible-computer-extension/dp/B002VG39BI/ref=sr_1_3?ie=UTF8&qid=1407678656&sr=8-3&keywords=usb+32+feetA bit of clarification. Not each camera should be connected to a separate USB port but each 2 cameras should be connected to a separate USB controller. Usually, modern PCs have 2 USB 2.0 controllers and 1 USB 3.0 controller. So for 8 cameras an additional controller is needed, which can be installed in PCI/PCIe extension slot.