Concerning the gas, the octane won't make a difference.
With the choke, depends on how cold your area is.
Is your choke the type that has a round black plastic cover held with three screws ?
If so open and close the throttle once to set the choke closed.
Loosen the three screws and turn the cover.
You want the choke to have just a small amount of pressure holding it closed, I assume your temperature is in the 40s or more.
Then tighten the three screws.
Fully depress and release the gas pedal three times and then try to start.