Hi I needed help with the lipo for a spektrum receiver and hitec servos, obviously I need to knock down the voltage for the servos so would a regular castle bec do it?

Also the lipo I was looking at has 2 plugs, would it be ok to plug one into the rx and one into a gas ignition? Would they both get 7.4 volts or would it cut them in half?

I think the rx and ignition will both be ok on 7.4 at least that's what I've been told, that it's only the servos that needs to be knocked down. I do have planes with regulators but to keep it simple I would like to use the bec if possible and only have one battery to keep it light. Any help would be great