I have thought about supporting hexagonal boards in the Interactive Diagram.
The way you describe it could be a handy stopgap, but I'd be more in favor of something specifically made for hex boards, treating W as a move to an adjacent hex, F as a move to a corner-adjacent hex*, and the rest as extensions thereof. The directional modifiers would be the only truly hard bit to figure out, I think, especially with t and w being the only unused lower-case letters for adding, but I suspect that a bit of brainstorming could work something out.
About castlings: one can of course think up any sort of crazy move, and present it as a castling option.
Well, my description of gO was just a random thought, taking the notation to its logical description, and not as something that would necessarily be useful. If the "cascading castle" you describe in the next paragraph after the above seems like a more reasonable (as well as more useful) interpretation, then I say you should go for it -- it's something that I could imagine using in a variant (though I'd be more likely to want a as its notation).
*An awful description, I'm sure, but I think you know what I mean there.
The way you describe it could be a handy stopgap, but I'd be more in favor of something specifically made for hex boards, treating W as a move to an adjacent hex, F as a move to a corner-adjacent hex*, and the rest as extensions thereof. The directional modifiers would be the only truly hard bit to figure out, I think, especially with t and w being the only unused lower-case letters for adding, but I suspect that a bit of brainstorming could work something out.
Well, my description of gO was just a random thought, taking the notation to its logical description, and not as something that would necessarily be useful. If the "cascading castle" you describe in the next paragraph after the above seems like a more reasonable (as well as more useful) interpretation, then I say you should go for it -- it's something that I could imagine using in a variant (though I'd be more likely to want a as its notation).
*An awful description, I'm sure, but I think you know what I mean there.