Don't forget that Jet and/or cigs decreases your CH, so even mentats won't help you, if you're under those drugs effect.
Also 1 ST and small frame is enough, if you're not BGer. Small frame is imba 1st level perk what should be taken to maximize build.
You'll need atleast 9 PE for sniper rifle, if you'll use cigs, else 10 PE.
1 ST and 1 CH is a base for all normal builds, as those are useless SPECIALs. Total you have 41 SPECIAL points (with Small frame) -2 on useless stats - 39. You have 5 stats left, IN is needed only for perks, so it's 6.
So you have 33 points on 4 stats: PE, EN, AG, LK.
+1 PE from cigs, +1 AG from nuka, so you total have 35 points on those 4 stats in the end.
The bad thing: you want to talk to Sha Enin or some other traders who require 3 CH.
Well, then forget about Jet and cigs, or make CH 3 and use them with mentats, or have 30 minutes impossible to talk to Sha Enins while you're under Jet/cig effect, and then take mentats to be able to talk to them.
3 CH means you can talk to traders 24/7, even when you're fighting, when you're lying dead, walking on world map or killing innocent. Those 3 CH aren't used constantly, what means you don't need it 24/7, you can raise it with mentats when needed, because you know when you'll use this 3 CH, and you'll take mentats in that time. You can always increase your CH on 2, while you'll never compensate it if you'll take 3 CH from begining.
Also focus more on speed of shooting than critical chance, better to shoot more frequently with lower crit chance than once with higher. Take BRoF over more critical, AG over LK.
You can also scrap EN, and make 9+1 PE 9+1 AG 10 LK character, but you'll die instantly if alone.
So if you're not afraid to be killed with simple smg or minigun then:
1 9 4 1 6 9 10 and damn, you still have 1 SPECIAL left, I hate when you have too much SPECIALs and don't know where them to put to! Really, I don't know where to put it. IN? 7 IN? What for? Well +40 skill points. Oh, also with 7 IN and under mentats and Night person trait (lol) you'll be able to take Doc3 prof at night, because you'll have 9 IN and will be able craft mentats with your own character, but you'll need to get FA to 150% and doc to 110%.
Or get 6 points into EN to make it 10, don't raise IN to 7 and then remove 5 points from.. something else. 2 from AG and 3 from LK, because there's no other choice.
In other words:
If you want to be sniper who can talk to Sha Enin, then you'll need to be non-drug build (still can use nuka cola), with 1 CH who uses mentats, or 3 CH drugged powerbuild ahahaha! 3 CH powerbuild! To compensate CH lost from Jet and cigs.
There's another idea: scrap cigs, have 1 CH, use only Jet (-1 CH), drink beer and eat meantats to get +3 CH total to 3 CH. You really need to talk to those NPCs?