Hi!
Use less nitro when using a hot glow plug!
5% nitro will be just fine togheter with an OS 8 or Enya 3 glow plug.
You will see that the OS .46 LA will run just as good on such a low nitro content.
11x4 or 12x4 is the prop size of choice if you fly at sea level. APC, RAM or Graupner "Sonic" are the best props.