How many times did you reload to get a planet sign?
What was the stats on your planet Sapdragon?
Well I've only gotten one. Saved it in a new file in case it was super rare and went back to try for double planet and looks like I was right to do so. Haven't got another Planet since! Couldn't tell you an actual number though. Oddly enough I did get the Planet sign after only about 5 tries. lol
I did level it some so i cant look at the stats but I believe the hole right side was the same, attack was 21, magic attack was 24 and im pretty sure acc was 23.
Either the Prima guide is wrong or there is no double planet Sapdragon. Familiars only ever have up to three possible alignments. Basic, double basic, and then -either- planet or double planet. If it can be one, it can't be the other. So if you can get a planet Sapdragon, you can't get a double planet.