The articles from Microsoft are all over the place with this one, but the correct syntax to add multiple servers as valid time sources to the PDC emulator is shown below. I typically use the pool servers in the US area of ntp.org, but feel free to substitute as needed.

w32tm /config /manualpeerlist:“0.us.pool.ntp.org 1.us.pool.ntp.org 2.us.pool.ntp.org 3.us.pool.ntp.org”,0×8 /syncfromflags:MANUAL /reliable:yes

Note that the begin quotation mark goes before the list of server addresses, but NOT the colon after /manualpeerlist. I’ve bolded the quoation marks in question to highlight them. This is the piece that many websites show incorrectly.