That sounds like a tough one and I may be totally be off base since I don't know the total situation with your engine.

How much time do you have on the engine? I have sometimes found it necessary to run a tank full or two during break-in before I could lean the engine enough to keep it running without the battery. I would also suspect that it will take about 3 gallons to complete a good break-in. I'd run several tanks on the ground, then fly with the engine slightly rich and not stay at one power setting the whole flight.

Another thought, many large engines require less oil than smaller engines. Volume, as the amount of fuel, is a cubic function, while area, the surface to be oiled, is a square function. As displacement goes up, the volume of fuel goes up faster than the inside surface area. All this means you need less oil in the fuel for the same lubrication than you do for a .46 or .61, for example. The bottom line is that you may need a lower oil fuel after the engine is broken in.

As for a plug, I would think the OS F or Fox Miracle would be fine.