I nominated some Tolkien ships before seeing this post, and I definitely think that the Silm/LotR books/LotR movie split is a good idea, and prefer that to any other option. One of the reasons is that I'm going to be requesting ships where characters technically appear, of sorts, in both Silm and LotR (I'm thinking of Galadriel/Varda, which I nominated, right now), but my prompts will most likely be Silm-focused. I'd be reluctant to request ships like that if there was a Silm & LotR books umbrella tag, because I want the Silm backstories for the characters and I wouldn't want to put someone who offered the pairing because both characters are technically LotR characters without reading the Silm. (And honestly, the Silm and LotR are discrete enough works that reading one doesn't necessarily mean you've read the other, and there are lots of fans who haven't read the Silm especially at all, so there might be issues on that front.) And for the book/movie split, I'm thinking that pairings like Arwen/Éowyn might cause issues if they're nominated, because the bookverse and movieverse characters have such different characterization and storylines.

I'm not planning on requesting Hobbit stuff for this exchange, so my opinion is probably not relevant, but I'd prefer a books/movies split for the Hobbit for the simple reason that the storylines diverge so widely from each other that they're barely both set in Middle-earth, and they tell different stories involving different characters from each other.

Thanks for dropping by! Are there any differences in canon/backstories for the Silm vs the LotR book version of pairings like you mention? Other than by omission, that is, or am I correct in assuming each book(s) just cover different parts of the same character(s) life and Silm functions like a prequel?

Also, you say technically they're LotR characters. Does that mean that while they are present in both they don't appear as much in LotR (book) as they do in Silm? Or are there other differences between books I'm not aware of, like comparing reboot or movie adaption versions of the same character.

You're welcome (or anyone passing by) to give me the Tolkien 101 summary of backstory differences if that may help illustrate your argument, given I'm only passingly familiar with the LotR/Hobbit books and not at all with Silm. At this point it does still sound like the books meet the shared universe requirements which other fandoms do, but I'm hoping a few more people might weigh in before we make a decision as I'm aware there are strong opinions involved.

While I realise this may not entirely set your mind at ease, remember that requests will be visible. If you're particularly concerned about being able to prompt for one version or the other (assuming we do combine, which isn't decided yet), I'd recommend getting your optional details and/or letter written and posted early in the sign up. Then if LotR only people really want to avoid needing to familiarise themselves with Silmarillion if they match with you, they have the option to watch the requests come in and decide their offers accordingly.

Someone has popped back in further up this thread about canon continuity differences within Silm, and has probably answered some of those questions I had about Silm - but if you have additional info you'd like considered, please jump on in!