Glow Driver & firewall measurment
The glow driver is called "expert" by Horizon Hobby...their house brand I think. It uses a regular 4 cell receiver pack (its own) which may or may not be good as far as additional weight is concerned. I use the extra pack for getting the right CG. It has an adjustable set point to turn the driver off or on. My last glow driver did not have that.
The distance between the firewall and the back of the spinner plate is about 142mm +/-
Here's a picture of the finished plane