Replication Delivery Requirements

I am about to output a project for replication and I am hoping someone can clarify my workflow and delivery requirements.

It's a DVD-9 (dual layer) video project. I have seen advised on the forum that it's best to use DDP 2.0, and that CSS is NOT recommended (although I was unsure why). And for some reason the DDP file should not be delivered on DVD (again, I was unsure why).

So my thinking is to do as follows (please advise if at any stage I am doing something stupid!):

1. Build the project and deliver the VIDEO_TS folder either via Toast to disc as a DVD-Video from VIDEO_TS burn, or via hard disc (USB Drive?)
2. NOT select CSS (why?)
3. Format to Hard Disc with DDP 2.0 then copy the folders (both Layer0 and Layer1) to hard disc (again USB drive?) for delivery for replication facility.

Any clarification would be much appreciated, or even just confirmation that I'm doing the right thing!

Thanks
Chris