How do Biblical Unitarians understand "the glory of the Father's own self" that Jesus claims he had before the world was?

From what I understand, Biblical Unitarians believe that the pre-incarnational existence of Jesus (as trinitarians propose it) is actually a notional existence in the mind of God. In other words, the Logos was not a person but only the notion in God's mind (sure foreknowledge or idea) of a person. An answer to this related question , "Do Biblical Unitarians teach a current, "notional", glory of Jesus?", indicates that Biblical Unitarians view Jesus, in John 17:5, as asking for the notional glory that he had with the Father prior to his birth to be made into a literal glory. In other words, although Jesus possessed only a notional glory prior to his birth (commensurate with his notional existence in the mind of the Father), Jesus now possesses actual glory (commensurate with his actual existence at the right hand of the Father). However, in John 17:5, Jesus appears to define the glory that he had before, the glory he is asking to be glorified with again (or have actualized, as B.U. might say), as the glory of the Father's own self: > 'And now, glorify me, Thou Father, with Thyself, with the glory that I had before the world was, with Thee; (YLT) There are some translations which render this as "..Father, in Thy presence.." but this appears to be a departure from the text rather than a clarification: >Together with the second person personal pronoun σε (se), meaning you or thee, the reflexive pronoun σεαυτου (seautou), meaning of thyself, or yourself. If Jesus had a notional existence accompanied by a notional glory, and if the notional glory he had was the glory of the Father's own self, wouldn't that mean that the Father's glory was notional? How do Biblical Unitarians view the glory of the Father's own self that Jesus claims he was previously glorified with and that Jesus asked to be returned to him?