A Believer: spiritual temple—the arrangement for pure worship.
What the WT actually says and I quoted above from the Insight book:
The inspired letter to the Hebrews states that in this spiritual temple the Most Holy is “heaven itself,” the area where the person of God is.
This most "Most Holy" is the "naos" that John says the Great Crowd is located in. There is no way around it A Believer. The evidence points to them being a heavenly class.
A Believer: Jehovah’s people on earth worship him in the earthly courtyards of his great spiritual temple
As stated previously, this is impossible, since "naos" did not include the courtyard of the temple. WT attempts to use this fabricated and incorrect logic to make their interpretation fit scripture.