Doing layout for an entire score with certain constraints

[tran li]

After I completed a score, I found that the default layout created by LilyPond is not satisfactory. I would like to modify some aspects of my layout, but doing that all manually can be extremely exhausting and create even weirder layout effects while adjusting. My requirement is as follows:

• Except for the first page that has 5 systems, all other pages should have exactly 6 systems.
• One line should have no more than 5 measures.
• The last page must be filled to the bottom and leaves no blank.

    While I am manually adjusting my score, sometimes a page of 6
    systems is broken in two pages that have 3 systems each, or a line
    is broken into two lines. I cannot exactly figure out why and when
    exactly this happens. So is there a more efficient way to achieve my
    desired layout requirements? I'd appreciate it if it can me done
    with more ease. If a specific score example is needed I'll provide
    it later.