Kjell,

1. Yes, oddino`s regulator the same as Jaccio.
2. In the setup I described I did just as you are contemplating. 2 batteries, 2 regulators (5.4v and 5.8v) one plugged into the battery plug on the RX, the other into a spare servo plug. If you don't have a spare servo plug you can use a splitter.
3. 400-500mah Li-po will be plenty as each flight (glow setup) uses around ~180 to 250 mah depending on vibration and duration. Just check the main battery before each flight.

I've also gone to a Li-po for my primary battery, they are much lighter.

Keith B