I like to set my TX to fast idle with the trim button. I usually start there. It's hard to tell you exactly how much the carb should be open for that very first start. I wouldn't open it up to 1/4. Thats a lot and is dangerous. Anything just above idle will allow it to pull in enough air to fire. If it won't fire try and crack it open a bit more.

Of course you want to choke it first and get it wet................. had to say it. Ya gotta be a lawyer around here or somebody will call you an idiot for not mentioning it.

Will you be using an electric starter? Or hand flipping the prop?