When I wrote my first draft and my friends read my first chapter there was a lot of excitement. Yes, it was long (57 pages!) it was full of errors and just generally needed tightening and shortening, but it entertained nonetheless and my friends wanted to read on. Success!
They also encouraged me to make the book suitable for publication so I always had that option, even though I started out writing purely for my own pleasure. It didn't seem like much of a stretch to work out how to make smaller chapters, bring the book down to a publishable size etc.
But chopping the book meant making some hard decisions, losing characters, sacrificing sub-plots and losing some of what people had enjoyed. I justified it as necessary because that is what everyone does. And the cuts were all over the book, but the first 57 pages were hit hardest. They now stand at 34 pages and when someone read the first 20 or so recently her comment was that I appeared to be hurrying through far too fast, that scenes should be opened out and that some of the narrative had become synopsis-like in my haste. I saw what I could do to the chapter to make the transitions smoother and show just the most important information on the characters, skipping the tell, but I stopped short of making the changes. I know why. Those original 57 pages are still in a box next to me and how different they were to the extract she had read. My heart wants to open the box and let out the original 57. That chapter just sang in a way the replacement doesn't.
What would you do? Would you open the box and re-cut the original (this was a job and a half the first time and there is no guarantee I would do it better) or would you take the 34 pages you have and restructure?
I'm not sure how much help I can be, as I've never written anything long enough (many congratulations, by the way - I can only imagine the dedication and hard work that a novel-length manuscript must demand) and you may already have considered this, but what about not using chapters all together? You could split the book into sections instead, and have the original 57 pages as Part 1 - you did mention above that you could think of it as being in sections. That way, you wouldn't need to worry about cutting it more brutally than you'd like. You could just have it split into paragraphs within each part, rather than dividing it up into chapters. Ian McEwan has done that in quite a few of his books, and I think that it can work really well - his novel 'Saturday' might be the best example to look at if you haven't already, as it is longer than some of his others. One of the sections is about 60 pages, too!
Sorry, I know that wasn't exactly what you were asking - but in answer to your original question, I think I'd be tempted to re-edit the 57 pages on the principal that it is generally easier to take away rather than add (though maybe 'less painful' would be a better word than 'easier'!) You say that the original sang in a way the edit doesn't - maybe ask your readers to say specifically what they loved about the first version you showed them. I'm sure editing must be a lonely and somewhat dispiriting business, so maybe doing it almost in collaboration would be a good idea. As I say, though, I have no experience I'm afraid.
I hope I've been of some help, at least - and very best of luck with it all.
I would simply recommend the resort I have turned to - get someone else to look at it... preferably some kind of professional.
I find that the biggest trouble with "adjusting" my own work is that I am just standing far too close to it.
I don't have to agree with any suggestions that are made.
:-)
If you concerned about when too 'Show' and when too Tell', you could invest in a copy of 'The Elements of Style' (Paperback) by William Strunk Jr. (Author)
Stephen King quotes from 'The elements of Style' in his book, ,On Writing'.
Used copies of 'The elements of Style' are cheap. You can look inside the book on Amazon, and then decide whether it is a worthwhile purchase.