The most important attribute of this heavier, stable element is that the gravity A wave is so abundant that it actually extends past the perimeter of the atom. These heavier, stable elements literally have their own gravity A field around them, in addition to the gravity B field that is native to all matter.
No naturally occurring atoms on earth have enough protons and neutrons for the cumulative gravity A wave to extend past the perimeter of the atom so you can access it. Now even though the distance that the gravity A wave extends past the perimeter of the atom is infinitesimal, it is accessible and it has amplitude, wave length, and frequency, just like any other wave in the electromagnetic spectrum. Once you can access the gravity A wave, you can amplify it just like we amplify other electromagnetic waves.
And in like manner, the gravity A wave is amplified and then focused on the desired destination to cause the space/time distortion required for practical space travel.
This amplified gravity A wave is so powerful that the only naturally occurring source of gravity that could cause space/time to distort this much would be a black hole.
We're amplifying a wave that barely extends past the perimeter of an atom until it's large enough to distort vast amounts of space/time.