How should graded numerical parallelism in Hebrew poetry be understood?

Pr 30:15 ¶ The horseleach hath two daughters, crying, Give, give. There are three things that are never satisfied, yea, four things say not, It is enough:

one The horseleach is a word riddle representing God. The five letters of the word give us five statements about God. There is one God who has divided Holiness and Grace who has the heart of knowledge, and is the light of creation. He is the only Holy God who gives of himself. This speaks of Christ.

two The word for 'give' also means 'ascribe'. We are to ascribe to the Lord Holiness and Grace. This is how we "acknowledge God as God". Two always represents an earthly and heavenly aspect of a thing.

three The three things which are unsatiable are the Father, Son and Holy Ghost since of the increase of His Kingdom there will be no end. Three is always related to the Trinity.

four Always relates to the four voices of God as Prophet, Priest, King and Judge, therefore the four solutions given in v. 16 relate to the voices:

v.16 1. The grave; 2. and the barren womb; 3. the earth that is not filled with water; 4. and the fire that saith not, It is enough.

five Why did it stop before five? Five is the number of man. The first four speak of Christ. But the question points us back to one which has five letters. The meaning of horseleach is buried deeper than 2,3, and 4. It requires the meaning of letters to come into play, not just of the words and metaphor. So the riddle closes the loop by pointing back to the beginning. Is there any reason to believe that all numerical parallelism will use the same 'tricks' of riddle? No. But the same metaphors used here will be used everywhere they are found.

The second riddle again mentions the Trinity. The four things that follow each represent the Word of God, and are related, each one, to one of the voices of God as Prophet, Priest, King and Judge. The resolution of the riddles give deeper insight into the Word. The Trinity speaks in four voices which is the meaning of 12. The Trinity is the one speaking, the four voices are the whole revelation of God.

Hints:

   Eagle is the Spirit
   the word for serpent also means 'brass' as in the 'tinkling of a brass'
   ship is a pun for 'me' or 'I'
   and the man and the maid are Christ and his bride

Happy meditating.

The main question is "how do we interpret graded numerical parallelism." The parallels are overlaid using drash so that they speak of one topic. In this case (and all cases) Christ. The the clues given by the numbers are used to match the verse with known metaphor which is consistent through scripture. Ultimately, the composite with all the clues from others scriptures are used to produce a Christological interpretation.

So effectively, graded numerical parallelism should be interpreted the same way as all other sensus plenior.