Hi!
Agree fully to what Brutus 1967 says on setting the carb ...but bear in mind that all these .40-.40 glow engines could run on just 5% nitro, be it OS, ASP, MVVS, Webra, ENYA or Rossi.
It is totally a waste of money to use more nitro. A good glow plug for all these engines is either an Enya 3 or OS 8 plug.
Props could be anything from a small 9x6 to a 13x4, and anything between..We are nowadays running the OS .46 in Q-500 pylon racing planes here in Sweden (earlier only .40 engines) and a .46 OS turns a 10x6 prop (RAM or Graupner G-Sonic which are the best 10x6 props) at around 15000rpm using 80/20 fuel.