Dies and Interchangeable Parts

So, I'm looking to make some jewelry pieces which use individually painted enamels in mass-produced settings.  For that to work, the enamels need to be uniformly shaped (I'm working with a slightly domed oval). I have been using an acrylic die in a hydraulic press to shape to copper I'm enameling, then cutting and grinding them down.  It has worked, just not amazingly.  My die is a little on the wonky side, resulting in slightly eccentric shapes (exacerbated by the fact the edges aren't crisp enough to follow easily when I take them to the sander).  Here's a (kind of crappy) photo of the finished enamels.

For reference, the graph paper squares are 1 inch by 1 inch.  I'm pretty happy with the painting, but the circumference difference between the smallest and largest pieces is about 5mm.  In terms of jewelry sizing, that is really big, and limits the options for setting types.

So, I'm trying to come up with something better. Jewelry supplier Rio Grande's commercially available oval cutter is a. really expensive and b. too small.  I've just found Potter USA's dies, which are much cheaper but mostly made for circular press setups (which may or may not be an issue).  I'm going to keep searching, but it may be my best bet is to have something custom made, at least for forming.  I'm still not sure about better cutting options for the formed copper, though this looks interesting.

In any case, if I opt to have a simple steel silhouette die made, there are a number of water jet cutting services available, so if need be I'll have a plate cut rather than resulting to an expensive custom die manufacturer for industrial use.