Using DVD to upgrade OSX 10.4

I am upgrading a G4 Powerbook to OSX 10.5. Do I use a single or double sided/layered DVD with the (included with Powerbook) Matshita DVD-R UJ-825 to upgrade?

The vendor is asking:

"Single sided DVD 10.5 Leopard is for clean/fresh install only.

The dual layer DVD 10.5 Leopard is for both upgrade and clean install.

Which one does your DVD player support?"