Thanks so much
Agi, Per, Luck. As for perks concentrated fire and all the critical related perks along with your weapon of choice +damage perk. These are the most important ones imo.
ooohhhhhhhh.... this gave me an idea....a ghost or VIRUS (in the pip boy software) like enemy that only shows up in vats to attack you! Like the opposite of the mysterious stranger...
As mentioned, Perception is needed as it will boost your VATS accuracy. Agility gives you more action points, and Luck has awesome damage bonus critical perks that are needed like Better Criticals and Critical Banker.
You can also find some armor or mod it, to help reduce AP cost in VATS, as well as give a slight AP increase. Like Ultra Light mods on your Combat Armor will boost AP a bit.
My advice: Focus on pistols as your main weapon type. For stacking up the most hits in VATS, unscoped pistols are your best bet. With 5 AGI and a 10mm you can empty a full 12-round magazine in VATS, I think.
Whether or not you start with 10PER or 10AGI depends on whether you'd rather start with Concentrated Fire or Gun Fu first, although you'll eventually want both in the end. I'd recommend starting with at least 7 Luck, though, for the joy that is Critical Banker.
The perk that when maxed (only 2 levels of it) refreshes your AP 50% faster is pretty awesome.
I have a Ag:10->11 Pe:10->11 Ch:Rest (for getting shoppes), remaining stats: 1, build that is a VATS killing machine. Coupled with military fatigues, eyeglasses, and military cap (or whatever), you get Ag and Pe as 14 base, before any temporary modifiers. Max ninja and I went commando with a certain extra bullet unique max'ed out (takes forever, lol), combined with that Lvl 10 Pe perk makes my character a beast. I don't like how luck is implemented at all now, so I don't rely on criticals, but it's still fairly easy at survival. The beginning is tough due low armor and practically no endurance, and you probably want to postpone armorer/gunnut/science perks until late in the game, which means you have to be on the lookout for weapon and armor mods from your enemies, and/or vendors. At lvl40+ I have not a single perk in gunnut, but my belowed 10mm and .45 double bullet are still completely max'ed out. And they're the only two guns I ever use, other than the occasional fatman should I come across one (will be sold anyway).