The Safe Check method seems like a rather hard way to figure the strength and power of each piece. Why not just compare how many squares each piece can cover in one move? Obviously some of the piece's positions when doing the counting will have a great impact on the total, but some sort of average can be figured into it. It seems like the value that is assigned in regular Chess should be adjusted to the game situation. That's what I do when deciding to make a trade or not. Sometimes a well placed Knight is worth almost a Rook. Especially when the position is blocked with lots of Pawns and both sides have a Bishop to keep the Pawns guarded.

A Rook's total number of squares that it can move to on an empty board doesn't change regardless of where placed. Always 14. On the 8 X 10 board a Rook has 16 squares to move to regardless of placing. All the rest of the pieces gain squares to move to as they get away from the edge of the board. The Chancellor and Archbishop are interesting to compare to each other this way. A Chancellor can have as few as 18 squares and as many as 24 on the 8 X 10 board. The Archbishop as few as 9 and as many as 22. It seems from just casually looking at this analysis that the Archbishop is a piece to try to get into the center of the board and keep it there or near there, and the Chancellor can stay away from the center and still have good range. More Rooklike than Knightlike. Both of them are trouble against the opponent's King. The Archbishop seems to work real well against the King when the position is cramped with its ability to move diagonal and get around the Pawns with its Knight move too.
This is what I've figured out so far. Still learning. :)