I can’t find any style guides about dealing with multi disc singles. For example PJ Harvey has some singles released on island records with catalog numbers started with CID and CIDX, where CID mean CD1 and CIDX mean CD2, but actually this releases are sold separately and information about cd number is not mentioned on its cover.
“Send His Love to Me” - https://musicbrainz.org/release-group/56173ebf-2fc3-41d3-9c90-481ffa135b0d
“A Perfect Day Elise” - https://musicbrainz.org/release-group/0708c3f3-5428-37df-aeda-fb3e111ccd26
“The Wind” - https://musicbrainz.org/release-group/f45350cf-3af0-360d-a135-1958caf396f5
“Good Fortune” - https://musicbrainz.org/release-group/c70e138e-c634-312e-b9b9-fa50533ba52f
“You Come Through” - https://musicbrainz.org/release-group/ea9b2297-e049-3c7d-8008-2be595e2ed9c
I believe that these releases should have the same formatting style, but some of the releases has something like (disc 1) or (disc 2) in they album title and some of the releases has CD1 or CD2 in the disambiguation field. Which style do you prefer?
Also, what do you think about creating an additional (but not existing in real life) box set with 2 mediums just for organising purpose and how it should look? Which release status it should have and what would you write in disambiguation field?