You definately want high def's and a hidden planet lol, yes planet slot 1 is the best for energy meaning it will take less time/res to do it. However it costs a lot of crystal and you want someone you know to crash it for you afterward so you can get the DF if theres no moon. If you just let the sat's sit someone will surely come along and take it for you lol.
Alot of people use rips as def's and only send them to attack if they get a chance to make a huge profit, or (heres the fun one) if you piss someone off enough that has them and you have a moon Deathstars are the only ship capable of desrtoying a moon, but like a moon they only have a certain % chance to deestroy it and there is a possibility that the "RIP's" (Deathstar) themselves can be destroyed.