Just use a switch, one cable out of the receiver and then each lnb connected through the switch and use switching in the installation menu. Not possible with a sky box.
In my opinion the dish should be pointed at Astra 2 28 for best quality. For my set up hotbird 13E channels are weak on an 80 dish, since you are picking up the reflection. I use an inline amplifier on hotbird to get all signals.