Nice easy way to do it.
You might consider, though, the likelihood it''ll look like crap if the running time gets much over three hours. In that case, I'd reauthor in DVDShrink, save with no compression. Then run it through DVDRebuilder at half D1, or half resolution. It's part of the DVD spec, so it's valid, almost any player will accept it. The picture will be slightly "softer", but much less chance of artifacts.