How long for a 8 lb prime rib

I just received my Anova at Christmas and love it!  I want to cook an 8 lb prime rib for New Years.  How long do I need to cook for and at what temp.


C

Here is a link to a site I trust. I have not done a prime rib but would follw these instructions.

http://www.modernistcookingmadeeasy.com/info/modernist-cooking-blog/more/how-to-sous-vide-prime-rib