Now I've had the chance to use my recovered darts alongside the replacements I can see a couple of differences between them. You can see in the picture the new gold ones have a slightly longer grip area and the the part where the point joins the barrel is slightly less bulbous. The new ones are exactly 27.0 grammes as opposed to 26.9 (they are laser etched with their weights to 0.1g precision).
These differences cause no problems at all, but the grip on the new ones is far more effective, and this is causing a worse release and my darts are veering to the left. I think this will decrease as they take a bit more damage and become smoother, but in the meantime I'll use the old ones for matches and the new ones for practice. Overcoming the poor release on the new ones seems to help overall technique when using the match darts, so I think this arrangement will work well.
Now I have tried these in both the Latinum and plain finishes I can see the benefit of Latinum. Maybe it is best to get them in this smoother finish and then roughen them up with the blade of a metal file if required. The pattern on the plain finish is extremely grippy.