Not much chance at this point, as I don't understand the promotion rules at all. You have both promotion on capture and promotion in a zone, and for the latter different rules for last rank and other ranks?
Promotion in a zone with choice can be configured through promoChoice, and this offers the possibility to restrict some choices to a smaller number of ranks, forbid them on last rank (usually for deferral), or restrict them to pieces in the holdings. You can cause captured pieces to go into the holdings (without color flip) by holdingsType=1.
Promotions to a fixed type at a certain location can be configured through a morph board for the promoting piece types. There is currently no way to make such a promotion optional, or if it is optional, restrict it to pieces in the holdings. This could be useful enhancements of the Diagram script, though. The same holds for promotion on capture through the captureMatrix.
Not much chance at this point, as I don't understand the promotion rules at all. You have both promotion on capture and promotion in a zone, and for the latter different rules for last rank and other ranks?
Promotion in a zone with choice can be configured through promoChoice, and this offers the possibility to restrict some choices to a smaller number of ranks, forbid them on last rank (usually for deferral), or restrict them to pieces in the holdings. You can cause captured pieces to go into the holdings (without color flip) by holdingsType=1.
Promotions to a fixed type at a certain location can be configured through a morph board for the promoting piece types. There is currently no way to make such a promotion optional, or if it is optional, restrict it to pieces in the holdings. This could be useful enhancements of the Diagram script, though. The same holds for promotion on capture through the captureMatrix.