They don’t do pads for saint/zee at the moment. I emailed them a few months ago to ask.
The absolute best pads I have found are brake authority ceramic, they are what I use in my saints, however they are expensive, even more so than the stock shimano pads, but they are worth it for gravity duties IMO.
In order the best pads I have used (starting with the best) are-
brake authority ceramic
rahox hyper speed
ebc red
goodridge sintered
hope oem – just ok
shimano oem – starting to be not so good
superstar, hayes, formula and clarkes all just plain crap
I weigh in at 120kg so I really notice the performance differences far more than most people would.