# How to manually typeset text in parallel on facing pages in (Lua)LaTeX?

I want to typeset a bilingual text in parallel on facing pages using LuaLaTeX. The existing solutions to automate this task have proven unsatisfactory as they don't allow for footnotes (parallel), don't allow for different font sizes of the two parallel texts (eledpar), or generally provide a poor result of aligned text chunks (eledpar).

As the text is not too long, I really came to consider breaking the pages myself. For this to do, I have to solve the following problem(s):

Consider two facing pages with ending paragraphs of different length. The following paragraphs should then begin at the same vertical position such that the beginnings of these following paragraphs face each other. For this to accomplish on has

1. to determine the position of the end of the longer paragraph on its page
2. to have the means to let the next parallel paragraphs both begin at the identified position.

Is this something which is doable? Are there mechanisms provided by (Lua)LaTeX to determine positions on a page and to begin typesetting at a specific position on a page?

EDIT: The following example illustrates the task. Here the latin paragraph starting with "O tempora, o mores" (third chunk of text in the code) should begin at the facing position of the beginning of the paragraph "Shame on the age..." (fifth chunk).

\documentclass[a6paper]{scrbook}
\usepackage{fontspec}
\usepackage[latin,english]{babel}
\begin{document}
\mbox{}\pagebreak

\noindent\selectlanguage{latin}{\large quo usque tandem abutere, Catilina, patientia
nostra? quam diu etiam furor iste tuus nos eludet? quem ad finem sese effrenata
iactabit audacia? nihilne te nocturnum praesidium Palati, nihil urbis vigiliae,
nihil timor populi, nihil concursus bonorum omnium, nihil hic munitissimus
habendi senatus locus, nihil horum ora voltusque moverunt? patere tua consilia
non sentis, constrictam iam horum omnium scientia teneri coniurationem tuam non
vides? quid proxima, quid superiore nocte egeris, ubi fueris, quos convocaveris,
quid consili ceperis quem nostrum ignorare arbitraris?\par\newpage}

\noindent\selectlanguage{english}When, O Catiline, do you mean to cease
abusing our patience? How long is that madness of yours still to mock us? When
is there to be an end of that unbridled audacity of yours, swaggering about as
it does now?  Do not the nightly guards placed on the Palatine Hill — do not the
watches posted throughout the city — does not the alarm of the people, and the
union of all good men — does not the precaution taken of assembling the senate
in this most defensible place — do not the looks and countenances of this
venerable body here present, have any effect upon you? Do you not feel that your
plans are detected? Do you not see that your conspiracy is already arrested and
rendered powerless by the knowledge which every one here possesses of it? What
is there that you did last night, what the night before — where is it that you
were — who was there that you summoned to meet you — what design was there which