Product technical sales information

Is there a site/document that explains the options that are listed on the Dell online order configuration pages? 

I am looking to replace our existing T620 server(s) with a T560 and am having difficulty getting a Dell rep that can define the options listed.  Things like "T560 Smart Value' for an additional 2 cents, what is the PCIe SSD/Flex Bay (pretty sure it's the right most 4 slots of the 8 slot 2.5 drive bay, but want to be sure before ordering), and how do I verify that all drive slots are connected to the hardware RAID (3.5, 2.5, NVME) even though I will not be initially populating all of those slots.  Just like the T620, I expect 10+ years of use out of this box and want to verify it can easily be expanded later.

Twice now I have started chat sessions on the order page to be told they need to call me, then never receive that call.