EnclaveKnight
It Wandered In From the Wastes
You will need a Perception of at least 7 to get most of the dialogue options with Chrsitine and a Perception of 8 for one dialogue check in particular; high Medicine and Science (70+) are helpful as well.
If you are not planning on getting Implants, I would definitely shift points from Endurance to Intelligence - you will get more dialogue options and more experience points, and honestly aside from getting implants, high Endurance is only necessary if you are planning to specialize in Unarmed Combat (which maybe you are; New Vegas establishes that Brotherhood Scribes are supposed to be skilled martial artists). Also, if you're planning on Tagging Medicine I think a higher Intelligence is in order, if only for roleplaying purposes - remember that 4 is considered "Below Average" Intelligence; only one point lower and you have dumb dialogue options! I would think somebody with a background in the BoS should have at least 5 intelligence, and if they have medical training/education I would bump it up to a 6 at least.
Uh, comprehension boosts skill magazines by double the normal amount (and requires only 4 intelligence), plus there is intense training to boost specials alone.
Okay, but my suggestion to boost Intelligence had nothing to do with skill levels, and a lot to do with roleplaying, dialogue options and SPECIAL stat checks (not the same as skill checks!).
If you want to use Intense Training to up your Intelligence you can, of course, but with a starting INT of 4 you'd need to boost it by at least 2 before you'd start seeing extra dialogue options, and probably by 3 if you wanted special dialogue with Christine and other characters in Dead Money and Old World Blues. Three ranks of Intense Training for a single stat seems like a waste of perks to me, but it's up to you of course.
If you're really averse to raising INT above 4, you could just take Mentats to temporarily raise your SPECIAL, but you also said you try to avoid chems in gameplay (not sure why you'd avoid chems but be okay with magazines, unless it's for roleplaying purposes), so I would think that's all the more reason to up your INT.
Like I said, unless needed. Like Med-X would be okay, Mentats when dealing with a computer would be fine, unsure of anything else.
I understand, but even 6 I would consider over the top. Do not need all that for everything.