Slumping temps are lower
Slumping temps are lower than traditional fire polishing temps. However, depending upon to what degree (as in how smooth, not how hot ) you coldworked, the edges may look fine with just a slump.
I have found that starting with a 120 grit diamond pad (on a lap), moving to 400, and then slumping, provides a nice edge. I slump at fairly low temps — no higher than 1220 in my particular kilns (and quite often I skip to anneal before that). Obviously, that depends upon the size/shape you are slumping.
Jester’s Baubles Fused Glass Designs