Sizing virtual Altiris Notification server( CMS 8.x)

We are looking to size our Nitofication server properly in the virtual environment. According to "Planning for Implementation guide", if there are more then 20,000 endpoint to manage, the virtual machine for notification server needs to have 32+ vCPU and 64GB+ RAM. Has anyone ever use this big virtual mahcine for NS? To me, I am ok with 64+GB memory. However, 32+ vPCU is more for hardware server instead of virtual server. Does anyone has any suggestion or experience in sizing virtual noificatin server to manage 20,000+ endpoints?

Thanks

Chunhui