Well, since one of the main reasons to have Phoenix is to get Thrawn (and Palp), you'll want them all at least G8 eventually, and more for certain toons. Obviously if you just unlocked GW you can't take them up to that gear level yet, but that's what you should strive for. If it were me starting over, I'd focus my gear on them until level 53 (you can complete G7 at that level), then start to build up other squads up (Scoundrels, Empire, Pilots, whatever) while chipping away at G8.