[Daniel Schneider]"They also said I could submit the separate layers on two separate DVDs. How could I do this, should I?"
Whether you can do it depends on the authoring program you are using. Scenarist and DVD Studio Pro make it pretty easy. These are the only two that I know of that can do it.
What you end up with is a folder (two folderd for a DVD9) that contain the exact same files that would be written to DLT. Simply burn the contents of the folders on separate discs. Probably best not to use Finder if your on the Mac. You'll need Toast to create a UDF formatted disc vs. HPFS format that Finder will make. Be sure to label the disc properly. You should have a Layer 0 (zero) and a Layer 1. Also, make sure to indicated boldly that the disc contain files for replication in the form of DDP files.