One is titled Infinitization of Selfhood, here is the official download link: https://makara.us/04mdr/01writing/07tg/Infinitization.pdf
Another is a series of four books titled Selections from Manuscripts. Here is the download link from Internet Archive: https://archive.org/search?query=“selections+from+manuscripts”&sort=-date.
These two could match up to, in my opinion, the Ra Contact Material both in terms of its volume and its quality. But the first one I shared is tilted towards the mechanical aspect of Intelligent Infinity and the second one I shared is tilted towards the spiritual aspect of faith.
As Ra have said:
You are precisely correct in your understanding of the congruency of faith and intelligent infinity; however, one is a spiritual term, the other more acceptable perhaps to the conceptual-framework distortions of those who seek with measure and pen.
And the author of Infinitization of Selfhood also wrote several other books. Hope this helps. 
My original plan is to share a zip file containing all the books I found that did a great job on philosophizing spiritually. But I have a concern that it will infringe the policy of the forum. By picking and selecting spiritual jargons and collocations from the two books that I have shared(and then by searching them on websites like archive.org(in the exact-phrase searching mode)), I think you could find much more hidden books that will expand your spiritual perspective.