General ⇒ Optimal page elements calculations

[meho_r]

Hi,

I was wondering what is the best method to calculate page elements (especially textwidth) so that every page (or at least recto and verso page in one page spread) begins and ends at same place (the last line is at same place on both pages)? I know of flushbottom command but it tends to add spaces between paragraphs which isn't nice. So, raggedbottom must be active because of this.

Which units are best used for defining margins, textwidth and spacing before/after sectioning commands, lists etc.? I presume that absolute units aren't the answer.

If one can provide example scheme for those, it'll be awesome. Let's say, i.e., B5, 2.5 cm margins on all sides, mathpazo, 12pt font.