Wow ! I feel your thoughts here are very much in line with what Jon Anderson was thinking in creating the lyrics and concept for the album
I feel all the 70s Yes albums have elements of spirituality (In the music as much as the lyrics) about them but each one in its own way; The Yes Album (Think Starship Trooper) had a futuristic sci-fi/spiritual aspect to it; where human understanding/exploration of the universe is a platform for increased spiritual awareness ; Fragile and CTTE looked at spirituality through man and his relationship with the natural world (Especially CTTE, with its 'foresty' and organic ambience in which the listener experiences a connection to a pristine wilderness of unbelievable majesty and vastness); Relayer was a spiritual quest seen through the struggle between good and evil in a LOTR type fantasy world (The cover art helps, but it's really within the music and lyrics too!). With GFTO, spirituality is viewed through several broader concepts; Human endeavour (Going For The One) Love (Turn of the Century) imagination and exploration (Wondrous Stories), and a quest for self-knowledge and self realisation - a more universal and general approach to spirituality (Awaken/Parallels).
And as for Tales, I always felt that each movement had a sort of textural signature that roughly corresponded to different physical environments. TRSOG was a misty, aboreal, impossibly huge rainbow eden; TR was a crystalline, shimmering, endless ocean, TA was harsh, cracked earth and the first flowerings of ancient civilisations within forbidding places, and their connection to 'The Source'. Ritual was a celebration of life, a communal gathering of reconciliation and joy with visions of some pristine atoll.
However, beneath the surface of these worldly physical associations, that come to mind (or rather through them) are deeper spiritual associations (which are touched on in the liner notes) of connection to something more profound which I think is best illustrated by the amazing conclusion to the TRSOG that occurs around 21:28, the phrase "I/we must have waited all my life for this moment". The way the lyrics and music play off each other here is incredible. It's difficult to pick out the detail in the somewhat muddy original stereo mix, but this section would have to be a contender for one of the most elaborate vocal arrangements ever. It seems to be a canon of many voices; (maybe 10?!) the incredible contrapuntal complexity creates a harmonic structure of astonishing beauty where the voices cascade over each other, the entry of each voice only compounding the beauty of the preceding one. This to me
is the 'ever opening flower' described in the liner notes. The way the word 'moment' flows in and out of the texture demonstrates how each moment cannot be seen in isolation. Past, present and future only make complete sense when viewed as one harmonious, timeless whole.
There is a book called 'Progressive Rock Reconsidered' edited by Kevin Holm Hudson, which contains an essay on the lyrical and musical concepts within Tales, and touches on some things I mentioned above. I spent many an afternoon leafing through it as a university student. Definitely an interesting read.
Anyway that's enough from me, happy listening