That's a nice gift... love personalized ones like that.
On my next go-around, I want to even out all the lumps.
Here's one suggestion for doing that, if it sounds like something you might like:
...roll out a long log of clay till it's almost
the diameter you want
....but, then make the log completely even
throughout its width by rolling over it with a sheet of plexiglas or glass (possibly from a photo frame) that's at least as long as the clay, to the final diameter you want --to make that technique work even better, also
hold the glass/plastic "roller" against the edge of your work table at the same time so that it acts as a guide for the roller
...shape your clef (freehand, or over a drawn or photocopied guideline on paper), cutting the log wherever there is an overlap, and pressing the cut ends to the other clay smoothing the join if necessary
...you could leave it like that
...or you could press down on the whole shape with the sheet of glass/plastic to flatten the whole top a little so it would be the same height and appearance all along its length
(..I'd also be tempted to rub on some metallic powder like Pearl Ex to the flattened part too to give it a bit of bling or visual complexity, and/or perhaps press down with a sheet of sandpaper, etc., first to texture that area)
(...since the clay could easily stick to the glass/plastic sheet, you'd want to put a sheet of paper between the clay and the glass/plastic when necessary ...or you could do that only on top when you flatten and just make and bake the shape right on another sheet of glass, tile, or metal/glass baking thingie ...or if you've used paper on the bottom, you can just lift the whole thing and bake it with the paper)
...you could also put a guideline drawn on paper under
the sheet of glass you'd make and bake on, which would do both things
P.S. I wouldn't use Sculpey (or FimoSoft) for this shape though because it's so brittle after baking in any thin areas... I'd go for a strong clay like Premo, FimoClassic or Kato.