Are triathletes still using these ISM saddles? I thought they'd gone out of style. These, second hand, a easy to find.
On AliX, i've bought several saddles, like fizik knock offs w a short nose and a relief channel, which is usually what you want to be in aero position. The 3d printed saddles so popular now also have that design, to a large extent (wide frontal area with a relief channel).
I've bought various saddles and sold the ones i didnt agree with, if you buy the heavy versions, they're usually super cheap, so you can experiment with what you get along with best for cheap. There's no 1 saddle fits all, anatomic differences, as even the bib itself can turn a great saddle into a bad one. Too many variables to have a gold standard, afaik.