For what its worth, the first tires on my car after restoration (see the old thread Tire Nirvana) were Pirelli P600 in the 205/70 size. I did not like them at all, and went to the Cokers. Don't want to start that debate again.
One issue I had with the 205-70 is that the spare would NOT fit in the trunk on my 280SL. Others had no such issues, which may say something about minor differences in identical tire sizes between manufacturers, and or the somewhat handmade nature of our cars...
One thing is for certain, tire sizes in the appropriate sizes are getting to be rare and thus costly...