I am a Catholic, but perhaps I could have worded it better, anyway, since the way I worded it, one could think I was stating it was merely present within the mass:
The Kingdom is present in the Church, made manifest (visible) within the mass.
So lets see if I'm understanding you correctly, Our you saying, the Kingdom is present in the Church (those that our his elect, whether Catholic or Protestant, or something else) made manifest(visible) within the masses of Christians whether in a physical Church or someplace else with the emphasis on a group of Christians being define as the Church, with no physical denomination or affiliation other then a profession of faith in Christ.
Or are you defining mass as a gathering of Christians whether Catholic or Protestant to celebrate the Eucharist.