I stand for the most part during the praise and worship, but for slower songs where I'm using sustain pedal, it puts all the weight on my left leg and foot and they start hurting, so i find that I can switch and sustain with my left foot....
It's a little awkward but works... then if there are other things going on I have a high stool that adjusts with a pnuematic lift so I can sit and still see what is going on. (I use an apex, so I can't go too low.)
Seems to work fine.
Jeff