If I create a custom position, by first selecting an empty 14 by 14 board, putting the king and rook on the same rank, and then select to have green and blue both dead, then O-O puts the King on the j file, while O-O-O puts the King on the f file, no matter what file I put the king and rooks on initially, but if I select XXL chess instead, then I find that O-O puts the King on the m file, while O-O-O puts the king on the c file, but if I edit the positions of the king and rooks at all then O-O puts the king on the j file, and O-O-O puts the f file.
I find that it's not possible to customize what file castling would put the king on, so if on a 6 by 6 board I wanted O-O to result in this
and for O-O-O to result in this
then I wouldn't be able to include it in any of my test games, as it's not something I could customize myself.
Similarly if I wanted capturing bishops to be worth 3 points in a custom game of points, then that also is not something I could include in my test games, as I cannot customize how many points players get from capturing certain pieces.
So my question is when submitting NCVs can we request special rules that we wouldn't have been able to customize ourselves, when playing test games, such as what file a king lands on when castling, or how many points players get for capturing a certain type of piece?