Yeah, is a good idea. But in some countries, the DVD9 it is still very expensive (like here in Brazil).
Anyway, sometimes its possible burn on DVD9, just put more Data.cabs on DVD.
In this conversion will not fit i think, (Data1.cab + Data2.cab), but Data3.cab + Data4.cab will fit on DVD9. So looks like this: 2xDVD5 + 1xDVD9.
But always makes isos and test if not have any issue.
You can also rearrange the files on Data*.lst's to fit on 2xDVD9.
