if you want a smooth talking gunslinger I would choose traits with +20% to aim with Guns/Energy Weapons plus Good Natured (+5 Speech, Science, Barter, basically all non-combat skills).
S.P.E.C.I.A.L - Charisma 9 + Luck 9, you can later add 1 point to both but I don't want to spoil anything to you and leave the rest to your liking.
With perks go with Gunslinger, all special speech perks, more crafting with guns perks, less weight with items under 1/2 weight (or something like that) + strong back, later on add more criticals or something + Mysterious Stranger and this second perk with this amazon lol ?
Of course I think I don't have to mention perks which allow you to distribute more skill points or gain additional +1 from skill books etc.
Weapon skills doesn't matter at the very beginning because you can have a pretty high speech/barter etc so you can talk your way through many situations, plus it would be a good idea to recruit some companions.
Besides don't waste your perks on things like Bloody Mess etc, it's pointless and it doesn't make a big difference with one shot high damage build like your gunslinger.
I've played with a build like that and it's amazingly fun, try it