How do you come up with their identification? is an interesting question.
My method for typing others in this forum, has a basis on their writing. Their writing may give some clue on their consciousness. But, before typing others you should already familiar with the cognitive functions. It would be hard trying to type other without it. Try checking their judging functions. Try finding sentences that falls into judging function. For example your in your writing, I check that this sentences
...that's more experimental
falls into judging functions. Next ask question further, since judging function in jung typology are only two : thinking and feeling, what judging function is this. When I have find that what is the judging function, try identifying their perceptive functions: sensing or intuition. According to Jung, a judging functions work in conjunction with their opposite perceptive function. So when I found your judging functions falls into extroverted feeling, your perceptive functions has to be only two: introverted sensing, or introverted intuition. When you have learnt that intuition is the function that deals with abstractions, insensatible perception, and i found that the person is rather theoretical than practical, I'll come up with the introverted intuition instead of sensing.
The more sentence that you analyze, the more accurate is the method.
But the method may be not really reliable to identify the primary function. For example in you, Once I identify as Fe and Ni, I still uncertain about which function is the primary and the auxiliary. When I mistakenly place the primary and auxiliary function, I could mistype you. Following this method, I could mistype you as an ENFJ if I hadn't able to distinguish between the type. I personally haven't met an INFJ in real life, probably because of their rarity. But I am pretty sure that I have met some ENFJ, so I am pretty sure I can tell that someone is ENFJ. Next I ask some spesific question for you that I know that ENFJ I know do well as a hobby, like sports or they seem to always hold some political standpoint, sentiment, which may distinguish them with an INFJ.
So when you are not like an ENFJ, because, there is no other type that use combination Fe and Ni, you must be an INFJ.
This typing method may not be reliable also, since the basis is only a writing, without inquiry to other data, only good as self exercising to try typing others. May be only intutive type will be successfully typed following this method. Sensor type may be not successfully typed accurately following the method, since they are more practical action orientated, that may not really be as themselves by writing. To type sensor, we should inquire more about what they are experiencing, what actions do they take, direct observation may be needed.
I expect that some read this thread and are willing to explain their method especially who seems to be motivated to type others. I notice that some type (mostly INTP) rarely mistype themselves in this forum. I have become curious of their method also especially for self identification.
Whatever the method is, the final identification should be affirmed that they are so and so by the person whose type is being identified, as the typer say, If he/she correctly identify. The person identified should realize that the type identification is for them. If the typers mistype them, it won't be useful for them. Like identifying your type as INFJ, has to have some use for yourself. It should add more self knowledge for the person typed previously that he himself did not know before typing. For example, you may want to know what are your unconscious aptitude that only accessible, executable, for INFJ.