Horizon View Network Design QOS

HI all..

I am looking to someone to help me out,

Basically I am researching the Implementation of QOS with regards to horizon view interims of network design..

Now my questions are:

1. Where should I the Stamp the Packets, ON the V-switch or the Physical Switch closest to the ESX hosts or on the firewall/router going out to the internet. Sorry I am not familiar with Horizon View..

2. The QoS Tag I should put should be AF41 from what I read . Is that still correct..

So if anyone could just give me some basic knowledge about QOS I would be great-full..