breitling's version does seem to have c and d scales, but it seems not to have a cursor, so it looks like it can't handle the very simple example i described in https://news.ycombinator.com/item?id=40324625 without a lot of extra mental work. and how would you do a square root on it?

the marketing shill splog page in your third link describes several other slide rule watches, but unfortunately it's too busy with huckster patter to explain what their capabilities are; i suspect they suffer from the same weakness