Plug looks a little long for that motor. It should be MR43T, RV9YC, BR6FS
Dwell 28 to 34*
Timing 8 BTDC
The choke needs keyed 12V power so when key is turned ON it's powered. It is grounded to the carb body so no extra wire needed
Yes turn screw in until it just touches, then back out 1 1/2...