Strip Construction Flip

I full fused a stip construction piece, and now want the shelf side to become to top of my finished piece. I like the crisper lines of the shelf side. However, that side did pick up some texture from the shelf and I want my finished piece to have a smooth and shiny top. I have read some about fire polishing but am a little unclear on the specifics. Can this be accomplished with another firing? Approximately what temperature and time hold to accomplish?

If that is not possible and the surface needs to be cold worked prior to the fire polish, what grit grinding would be the minimum, 60, 120, 220, etc.

Thanks in advance for any help.