Cwhipple,
First of, welcome to the RCGF world of engines, I am sure the engine will serve you well for many years to come.
By the way that you describe not seeing any grounding of the ignition, I am sure that you have not pushed the plug cap all the way onto the sparkplug. The ignition is grounded by the outer (shiny metal) cap that surrounds the sparkplug as you push it over. Now, this is an extremely tight fit, and requires a bit of pushing force to secure it to the plug.
The outer cap must actually split open around the bottom a bit for it to sit tight. Please do not bend the plug cap, you can however turn it on.

I am sure that this is the issue, as the Rcexl Ignitions are very well shielded and do not produce stray RF.
The plug is a resistor plug, and the best of the Torch range, and as you say it runs well, your problem is not here.
The 45cc RCGF, although not the most modern reed valve rear induction etc. is a very user friendly engine, that will run like a clock for hundreds of gallons and provide you with power not normally seen by a 45cc engine.

Hope this helps, shout if you need anything else.
Andreas