I have the exact same setup as you , 1970 auto 340/727 console /PS/PB and the stock large starter , no need for the mini starter .We had a mini starter just in case , but thee was no need for it so I saved a few $$ . Really the dif between headers and manifolds is not that much on a stock or mild build .
I had a set of hooker stainles steel headers and the pipes were pancaked , could not get down my driveway without hitting at least 4 times , and that was going super slow , under 3 mph . Have not hit my new pipes yet .
The reason I went with Tight tube hedmans is I could not find manifolds in good shape for a decent price .
Good luck , whatever the choice , enjoy the car .