Well, I recalculated the values for both piece types using my last
published model (which probably is not perfect ;-) ):
High Priestess:
8x8: 6+1/28; 10x8: 6+5/36; 10x10: 6+19/45
Minister:
8x8: 6+5/7; 10x8: 6+3/4; 10x10: 6+44/45
Let me admit, that now it seems to me more impressive, to scale piece
values no longer to a Pawn normalised as 1, instead to do it using a
Knight normalised to 3. This remains neutral to the pieces' values
relative to each other, but it seems to create more comparable value
series.
The High Priestess' strength is more vulnerable by a decreasing board
size. Values of both types tend to become equal at an unlimited board
size.