Jeff, in general you don't need to make starters with dry yeast - they have plenty of cells for full five gallon batches. Its liquid yeasts that people usually make starters for.
With your dry yeast you may rehydrate it, but you don't even need to do that. Just sprinkle in the cooled wort.
I don't know how much yeast you would need to pitch - or if pitching the whole packet would be harmful. I think you could easily go with half a packet.