Thanks for the info Mr. S and SML.

This whole project has been a DYI, especially to keep costs down.

I will design with 2 inches above the main components. Im am planning the 770 on the bottom and wiring coming out the base also.

How often do you need to "get behind the rack"? I assumed it would be a rare occasion after your system is set.

Is there a website which carries cable conduit? The way I am ending up, I will have a very open equipment rack, stair stepping alongside a storage built-in and the wires behind will be visible. Should help with ventilation also.

Suggestions at this stage are easy to implement.