On the German verb

This will probably seem silly to anyone who actually knows German, but I've been working on my reading competence and I'm finding it much easier to deal with compound verbs by thinking of a hierarchy of compositional elements.

The second position in the sentence of course takes the finite verb, and the other parts get kicked back to the end of the sentence.

The rank goes like this:

(1) Futurity (2) Perfectivity (3) Passivity (4) Verbal idea

Their ordering goes like this:

... A ... (D,C)B

It's that final position which moves right to left that seems tricky at first.

In English we have the same hierarchy but for the fact that ours reads from left to right.

Compare the following:

G. ... wird ... gesagt worden sein.
E. ... will have been said ....

If you remove any element, the hierarchy requires that the other elements take their proper place. If you wanted to remove the passivity, worden and been would both be dropped and their place would be taken up by gesagt and said, and the auxiliary of sagen (haben) rather than of werden (sein) would take final position:

G. ... wird ... gesagt haben.
E. ... will have said ....

In neither language is there any flexibility in the position of each element. If any of them is present it will take its place in the hierarchy.

Again,
German, ... A ... (D,C,B)
English, ... A (B,C,D) ...

Then again, I'm just a classicist struggling through this language. Go ahead and trash and/or correct me in the comments.