I would use whatever fuel is easily available to you locally and commonly used at your field. Your engine will run fine on 5%-15% nitro but I would probably start with 10%. it is a good all around fuel that will work in a variety of engines. I personally buy strictly 15% though since I fly a lot of 4-stroke engines but it still works fine in 2-strokes too. I run Coolpower that ha 18% (I think) synthetic oil. I have no problems running it in a brand new engines. There are a lot of arguments for using castor and that's fine but I do not abuse my engines and I have zero problems. Like I said, find something that is readily available in your area and stick with it; you will be fine.

A quality glow plug will last a surprisingly long time if you run good clean fuel and the engine is tuned properly. In 4-strokes, I easily have them last well over a year. In fact I only end up changing them sometimes because i want to play it safe, not because they are actually bad yet. A plug won't last quite as long in a 2-stroke but I still can't imagine changing it more than 1-2 times in a season. Regardless, keep a few extra on hand because they can go bad unexpectedly and you don't want to ruin your flying day by not having a spare.

OS has a good glow plug chart here:
http://www.osengines.com/accys/glowplugs.html

The #6 is a hot plug. I generally like a #8 since it is the middle of the heat range and it seems to work well in most 2-strokes. You can always go up or down in heat from there to tune the engine to your particular climate, fuel, etc. Since it comes with the #6 already though, I would screw it in and use it. I generally stick to OS brand plugs because they have good consistent quality. I have done well with plugs from Fox and others though.<br type="_moz" />