RE: CDI ignition battery in receiver or direct from battery
It's because I'm using Lipos and the CDI can take up to 6V, so one battery for the receiver the other for the CDI, on my setup I'm using the Digiswith for the Rx and the regular sw with the Shulman regulator, I'm at 5Kg with both regulators and dual batteries. If I use only one battery I need to use a bigger battery anyway, so weight will be increased anyway.
I saw in your diagram that you intend to use a 910mAh battery? I was using two Flight Power Evo 800mAh each and gave me 4 flights before recharging, I do not like to fly under 50% capacity, and the receiver and CDI take approximatly the same wich is about 110mAh each on a 12min flight.
Regards