As I understand it, all those old radials were started on the primer then bring up the mixture lever when it's running. Cessna 414 does that even today.
I spent a few years maintaining DC3 & DC4 and that's how we started them when we did engine runs. With 1 guy in the cockpit you moved the mixture lever out of the detent first and when the engine was running on the primer moved it up to rich with your foot. Take a look at the pedestal and you'll see that this is the only way.