I put the edge up, spine down in a rack.
My rack is metal, brick works fine but is bulky.
Inconel makes the best racks.(nickel,chrome, and iron)
It can really take the heat.
If you get a warp, straighten it within 15 minutes of taking it from the oven.
It must heat evenly and cool evenly as well to prevent warpage.
S/S is best if you wrap it in foil, C/S is quenched and you will fight the envelopes trying to get it in the quenchant in time.
(And you WON'T make it in time
)