It is challenging to understand how the NT writers use the Old Testament. At times it seems they may be using it in a completely different context from the way it was understood by the Old Testament writers.

And in Hebrews at least, the writer will cite something as applying to Christ which the OT says of God. You can see this repeatedly in Hebrews 1.

I found this interesting comment on Calvin’s understanding of this issue in Five Views on Law and Gospel in Willem vanGemeren’s chapter, pages 51-52, in which he is citing John Hesselink:

What is said of God in the Old Testament can without any twisting, manipulating or allegorising be applied to Christ in the New Testament, because when God is referred to in the bible, Christ is presupposed.

I’m looking forward to Commentary on the New Testament Use of the Old Testament, edited by Greg Beale and Don Carson, said to be available in the US in November.

I agree, understanding how the NT writers use, quote and understand the OT is tricky. I suspect part of the answer relating to how they speak about God will involve trinitarian issues and the nature of progressive revelation. In my view there is a great deal of hyper-Christocentrism in many corners of evangelicalism which read Jesus into every passage every chance they get simply because it sounds right.
Another big part of understanding NT use of the OT simply comes down, dare I say it, to the inspiration of the Holy Spirit. These guys were given insight by the Spirit to speak and write authoritatively in a unique way, so in Acts 2, Peter says that David (in Psalm 16) “foresaw and spoke about the resurrection of the Christ”. There’s a heap of stuff in the Psalms that could be allegorically linked to Jesus even though neither NT or OT explicitly warrants it. Therefore, within their cultural context, relative proximity (compared to us) to the OT events and having the Holy Spirit inspiring them they were able to discern real OT links that had relavance in a variety of ways to the person and work of church and the early church.
I’ve never really looked into this whole issue much. Reading the book that you’ve suggested will prove to be very interesting indeed.