Points of View

Still working on major fiction editing job, hence the woeful lack of posts on here. Most of the time, I have my head down over the laptop and only crawl downstairs occasionally for food and tea and - at the end of the day - alcohol! I love this process, but it is very difficult in that it involves a certain amount of wrestling with the tricky business of 'point of view.' This is something that most readers don't think about. It is also something that many writers don't actually think about either until hit with the problem of how to tell a story. Exactly whose point of view is the story being told from - and what difference will that make to the finished piece of writing?
Now I'm aware that there are lots of highly prescriptive websites out there, listing all kinds of 'rules' about this. I'm also aware that, wearing my other hat, as a playwright, it's something I tend to forget about as well, for the simple reason that when you are writing a play, you have to get inside the heads of ALL your characters. This is because actors have an alarming habit of asking you why their particular character is behaving in a certain way - and woe betide you if you don't know the answer, for even the most minor characters. It's extremely good for the writer, though, in that you can't get away with anything less than a comprehensive understanding of what you are writing about!
For this particular project, a novel, I thought I was telling the story - which is in the third person - from a particular character's point of view, but I see that I'm not. I'm telling it from the points of view of two characters with the odd digression into a third - which I believe is something called 'limited omniscient' - the writer is God, but only with regard to a handful of characters! Now, I am trying to introduce a body of material which is known in its entirety only to one particular character - and it's difficult, although it is also essential, in that I was short-changing one of my characters by deciding not to explore his background. Now, I know what happened to him. And he certainly knows it. But how should that knowledge be 'stitched in' to the story. Should I write it as a 'found' account - a device often used by writers - and one that isn't unknown even in non-fiction, witness an excellent and rivetting book called The Suspicions of Mr Whicher, by Kate Summerscale in which a letter from Constance Kent goes a long way towards clarifying previous events, but also includes its own element of mystery.
Should I - on the other hand - have him tell his tale to one of the other characters - something he has done to some extent in a previous version?
Should I go the whole hog and access his knowledge within the body of the book, thus making the whole thing more dense and rich. Or should I attempt some combination of all three - and see what happens.
It is, in a sense, a little like unpicking a complicated garment, retaining the fabric, but stitching it up again in a slightly different way, and any seamstress will tell you that this is actually a more difficult process than starting from scratch! I'm feeling my way into it, and - as it turns out - I'm working in layers. I don't make drastic changes all at once. I go over and over and over it, and feel my way into making the additions, and do nothing too major until I can see how the previous draft has worked. It is time consuming and tiring, but hugely interesting and - so far at least - it seems to be working.