BAT's 6H30 "Super Tube"

I would not recommend swapping the 6h30. It definitely is not interchangeable with the 6922.

Tenor Audio, LAMM, ARC and many others use the tube. It is a great improvement over the 6922.

No, the 6922/6DJ8 tubes cannot be swapped with the 6H30 or vice versa. There are significant differences in most cases. Several tube parameters are sufficiently different in that the tube would not perform well. Either swap would require circuit changes and, in the case of the 6H30, given its very high Gm (for one) would likely have parasitic oscillations.

What about the 6H23 in place of the 6922? And what differences would one expect?