I will be with you always

I often feel inches away from Christological and Trinitarian heresy. I am trying to puzzle over how we should understand the presence of Christ (especially in the Lord’s Supper) and what Calvin means by this:

What can be imagined more absurd than that the flesh of Christ was in heaven while he hung upon the cross? Yet undoubtedly the whole Christ, God and man, was then also in heaven… Christ, the Mediator, God and man, is whole everywhere, but not wholly, (totus ubique, sed non totum) because in respect of his flesh he continued some time on earth and now dwells in heaven. (‘Last Admonition of John Calvin to Joachim Westphal’, Calvin’s Tracts volume 2, Treatises on the Sacraments, p418)

Or again,

… Christ as mediator is everywhere, and in as much as he is one person, he, as God and man, or God manifest in the flesh, fills all things, although in respect of his flesh he is in heaven. (p452)

I feel am a bit confused as to what it means that the whole Christ is with us but not wholly but I think it goes like this:

The person Christ is everywhere according to his divinity, since as God he is omnipresent. Christ’s divine essence fills heaven and earth (p385).

But Christ is also seated at the right hand of the Father in heaven whence he shall come again in the same manner in which he went, according to his human nature, which, like any real human body occupies a certain amount space in a particular location.

We could add that:

Christ may also be said to be with us by the Holy Spirit since the persons of the Trinity indwell one another. The Holy Spirit is not Jesus but he is the Spirit of Jesus.

Further, the Spirit unites us by faith to the human flesh of Jesus which is heaven. Again, precisely what that means and achieves ....

Christ’s power and virtue, his empire and the secret power of his grace are everywhere (p457).

Any help / corrections most welcome!