The 3 turns in the manual is the setting for a new engine. It's going to be pretty rich if your motor is already broken in. Too rich is better than too lean, though. The glow plug has to glow bright orange or the motor won't start. That's critical to starting it.
I prefer a mix of 50-50 synthetic and castor at 11-12 % oil. I always used 25 % nitro. That's just what I liked. The oil you picked would work as well. Any fuel is going to be better than 25 year old fuel. You might find an oil lugie in the carb passages too. an oil lugie is oil left in the passage and all the alcohol has evaporated. The oil dries out and you're left with a gob of semi dried oil. I've used carb cleaner to clean them out without having to take the carb apart but sometimes you have to take it apart. . Good luck. It would be a big help for you to have someone experienced with nitro cars there when you try to start it.