I do not propose to have all the answers, but I do have some ideas and views that might help. As far as the question of wanting to be a Spiritualist goes, we should probably define it. I always had problems explaining what Spiritualism was to people who had no background in it, so I came up with my personal definition, as follows:
Spiritualists have three major attributes: a belief in God, which is left undefined and is the God of your understanding, a belief in Natural Law, the most common example of which is "what goes around, comes around", and a belief in spirit communication.
I would say that this quick definition barely covers some of the core and is not comprehensive, but it is still useful. It's something you can say to someone in three minutes, which in some cases, is all the time you're going to get. :-) I'd say it reflects the term as it is commonly used in the US and the UK (at least). In other countries (such as African ones), I've seen "Spiritualist" used to refer to anyone with a belief in spirit communication, and that's probably too broad for us to work with.
My theory is that if you can call yourself a Spiritualist based on the quick definition, then you'd probably be considered a Spiritualist in many/most places described above. Perhaps the biggest point of departure in Spiritualism is around atonement and Jesus. I would say that purest Spiritualism does not believe in vicarious atonement, nor in Jesus as savior. Jesus as medium, yes. Jesus as teacher and healer yes. But not savior, and not God - at least not any more God than the rest of us. Believing in vicarious atonement and Jesus beyond what I've said here is likely to be a variation of purest Spiritualism. Plenty of religions have variations, and Spiritualism has them too. I would still consider these variations as Spiritualism because they're still they're a lot closer to purest Spiritualism than many other religions we could easily name.
As far as the declaration of principles goes, there are plenty of variations of it too, as has been discussed in this thread. My view is that I like the NSAC version in the US more than some of the others, as it seems to speak more directly to the quick definition above. I wouldn't necessarily discount the other versions, I just happen to like the NSAC one better. My perspective is that I worry less about the words than the truth behind the words. As long as there's harmony between my beliefs and the truth behind the words, I'm ok. Some of the non-NSAC declarations leave me a bit curious as to what the truth behind the words is, but that's ok, because I can just ask. One thing I've learned from Spiritualism is that if you're not sure, ask.
I think that part of what you're asking is that if you're a Spiritualist, what do you "do", how do you "practice"? Spiritualism isn't terribly big on ritual and structured practice, and that can make it frustrating for people who are looking for it and/or expect it. Since there's so little of it, my idea would be to seek the company of like minded people. That could involve going to a Spiritualist church, or hanging out with a group of people that you discuss spiritual topics with, or both, or perhaps a number of other things. It depends on what you want, what you seek out, and what you encounter along the way. I've done it this way for many years now, and it's worked for me.
You know, when I started writing the above post, I wondered about whether to put the time and effort into it. I have put similar efforts into the group postings in the past and didn't get much response back, and after doing that several times, it made me wonder if it was worth it. But I did it. And the group member said that it was enlightening and helped him understand a lot more. That made me feel great. Instantly worth it. Experiences like this keep you going.