I haven't read anything except the OP headline (I will backread) -- but I felt like saying this: I initially felt extremely overwhelmed, however, I then started from scratch on each side and tried to take in the different talents and their values. It turns out to be quite fun, actually.
In addition, I would recommend this addon: Talent Tree Tweaker / Previewer, it allows you to mess with all specs from your own talent tree, save them, export them, import them.. quite a cool bit of functionality actually. It also shows which talents cause you to "go back" and which ones you can remove / de-select and not have it "restart" the previous tier. I hope that makes sense.
Check it out: https://www.curseforge.com/wow/addon...nt-tree-tweaks
(I have zero affiliation with any add-ons or their authors, just linking this because it helped me)