Here's what I would make of this passage. I wouldn't conflate the two versions, but would keep them apart. I would only use "cairtlibair" from E1 to emend "cailclibuir" in E2:
> > E2:
> > + in neoch ba hintaisfenta leis de doberidh glunsnaithe filidechte
> > fai, + nosgribtha aice he a chailc libair.
> > E1:
> > + docuir-sium glonsnaithi filed fuithib + doscrib-sum iat a lecaib +
> > i taiblib + rocuired (?)-seic i cairt liubair
E2: ocus [a/in] neoch ba h-intaisfénta leis de, do·beired glós*náithe filidechte foí, ocus no·scríbtha aice hé i cairtlibuir.
"and whatever of it deemed him worthy to be expounded, he would put the thread of poetry on it, and it would be written by him into vellum books"
I used "glós*náithe" instead of "glunsnaithe", simply because that's how the word is cited in DIL and how it is written in the glosses. But other spellings are found as well.
DIL explains "glós*náithe" as an imitation of Latin "filum" "thread", and suggests that "the original sense may be defining of delimiting thread or line...; hence typical form,
norm; passing into the sense weaving, arranging (of a composition)".
"no·scríbtha" is 3rd sg. passive imperfect.
E1: ocus do·cuir-sium glós*náithi filed fuithib ocus do·scríb-som íat i lecaib ocus i taiblib ocus ro·cuired-som i cairtlibuir.
"and he put the thread of poets on them and he wrote them in stones and in tablets and he would put them into vellum books"
The verbal forms in E1 are all Middle or Modern Irish. Take special note of the use of "do·" instead of "ro·" as perfective augment.