Just some thoughts on the topic...
I don't know how integrating from 1 to 4 looks like, but I know what it looks like the other way around. Through my teenage years I was an E4 at the core and then went to 1 as a core. My tritype was 461 back then, so the 1 was always there, but not easy nor hard to see. I noticed the 1 in me far less than the 4 and 6 however. Somehow my core turned into 1 through young adulthood and now I'm a 146.
I think the differences are quite big and I believe it's got more positives to go from 4 to 1 then the other way around, although most Ennea-pages tell you 4s go to 1 when they're stressed. I don't know about that since my core shifted from 4 to 1, so I'm mostly in my 1-behaviour now, even when relaxed. Back when I was a teenager I'd go to 1 when stressed or feeling comfortable. So the message 4 -> 1 when stressed doesn't seem to apply always...
I must add I'd also wish for a deeper analysis of the 1. The 1 is portrayed as this person who's obsessed with ethics. Aside from that we're often described as strict and critical and these few attributes make us seem like a caricature rather than a real person. There's more to a 1. I can only agree with what [MENTION=10791]sulfit[/MENTION] said here:
In contrast to 4s, 1s display more competence-based intolerance towards others: they have a perception of the way things should be or could be better, and other people aren't doing anything to improve them, or even making things worse. For 1s this perception incites an intolerant and critical attitude towards other people. 1s are close to 2s in the enneagram, and pridefulness is an issues for both to some extent. This is something that actual 4s don't have. 4s display emotional exuberance and indulgence that 1s rarely engage in, while 1s don't care as much about their image.
Can't agree with the next quote, however. But that may just be me:
One thing I get from his material is that types on the lower half of the enneagram are more ego-dystonic (painfully over-aware of their pattern), while he describes 1 as ego-syntonic. I wonder if that could make it difficult, like it was for your friend, for some 1's to hit on their true type.
I'm imagining someone reading about the moral discipline of the 1 in books and thinking they must be anything but that type because due to their extreme standards for themselves that they can only fall far short of, they feel inside like they are just barely in control. Maybe they'd choose themselves a type known for being more impulsive or more emotionally driven, unaware that their definition of "impulsive" differs wildly in scope from what the authors and healthy people in general tend to mean by that. Meanwhile everyone else around them does see a disciplined and a very self-constrained person. That person just can't see it in themselves. "I'm not critical...if anything, I'm too easy!"
While I am not easily satisified with my efforts and the results of my work and I do have moments when I can't stop my perfectionism although it's about to drive me mad, I am totally aware of my self-flagellation. At least when you have a 4 in your tritype, it should be extremely easy to notice. I know what I used to be like - 4's are way more hedonistic and indulgent - nowadays I'm not and it's easy to recognize. Total difference in .. well, discipline I find. (And competence and higher set of standards, you get the gist).
Last quote:
1s don't internalize the rejection or mistreatment they recieve from others as a reflection upon themselves (unless they feel they've violated one of their principles). The aggressor is always in the wrong in their eyes. This isn't to say that 4s are doormats, but there's often a part of them that confirms, or loosely identifies with the negative judgments of others.
That's not always true. Most of the time, yeah. Because we realize other peoples behaviour isn't about us. That's a common realization I've read online a lot of 1 make along the way. I wonder how come. It's weird.
The aggressor isn't always wrong, however. That's far off from how 1s cooperate during conflict and criticism. There's a thread here on TypoC too where a lot of 1's told the same story... they don't like getting angry before being sure whatever caused the conflict and criticism wasn't their fault. It's about examining what's the issue, getting to the bottom of it and doing the right thing, meaning, apologising if neccessary.
So much for perfectionism... it's a rather unpleasant process cause when there's a really huge conflict you break your head over the issue and spend so much time thinking. Thinking, thinking, thinking... and you don't stop not until you've found the issue and understand it %100.

