Waiting on full synth until 5k-10k is very old school thinking. In the "old" day full synth was too slippery to allow the piston rings to properly seat. Ring material and oil compisition have changed significantly in today's engines. Many cars today come with full synth from the factory.
I switch to full synth on the Raptor at 500 miles.
Agreed.
I always change the oil on a new vehicle after 500-1000 miles, then go to Mobil 1 every 3k miles thereafter.