Let us know how things go.... be interested to hear. I could not find the ASUS PCIe adapter.... do you have a part number?
Say, do you know if your Z620 is one of the original ones with the older motherboard type, or if it is "version 2" with the newer type of motherboard that can run the faster processors? The easiest way to tell the difference is by its Boot Block Date, as detailed in the forum here. That will make a big difference in processor upgrading.
Finally, I found my HP reference part numbers for the HP 2.5-to-3.5" form factor converters if you ever need those. The HP "tool-less" one that costs an arm and a leg is 675769-001:
Versus the HP "needs-screwdriver-for-1-minute" one that is under $10.00 USD on eBay, is HP part number 654540-001 and looks like this (with same quality metal and same Foxconn SATA BlindMate interface board):
