Saddle size: The rule of thumb (which seems to work well, so I have no reason to criticize it) is that you should take your outside sitz bone measurement and add 1-2cm to each end for wiggle room. That gives you the width of the saddles to consider.

Watch someone ride some time, they really do shift around on the saddle quite a bit as they change from downhill to climbing to flats.

Folks with a hip angle that feels best on "T" shaped saddles are at a disadvantage to those who can ride "pear" shaped saddles, I think. The "T" folks can't really shift front to back on their saddles like the "pear" folks. "T" riders just gotta get their buns up off the saddle more often to relieve/change pressure.