Attempting to install with Jun's Loader v1.03b DS3615xs and DSM_DS3615xs_23739.pat would fail repeatedly with Error 13.
Switched to Jun's Loader v1.04b DS918+ with this guide using DSM_DS918+_23739.pat worked. Only steps needed was editing PID/VID and Serial.
In BIOS, I've disabled C1E and the serial port. I don't think I did much else different from default BIOS settings. I can look at BIOS settings further if anyone is interested but I doubt it'll be an issue.
Intel Xeon Processor E3-1225 v3 3.20 GHz, 8M Cache
500GB S-ATA HDD
no diskette drive
Tower Form Factor
280W Power Supply