...As someone who is an Engineer in both temperament and training I ALWAYS do some testing and verification when starting a new endeavor. When I started using plated bullets I naturally experimented with different amounts of crimps and found that it was NOT possible to "crack" the plating on a quality plated bullet, even with a roll crimp applied with enough force to buckle the case on a 38 special. Method used to determine this was a 20X loupe and a bullet pulled from a buckled 38 special just showed a groove created by the crimp but NO CRACKS IN THE PLATING. Also shot those pulled bullets after reloading them in fresh cases and they didn't cause any noticeable leading.
I'll also point out that every one of Speer's bullets has the "jacket" applied by an "electro chemical process" per an informational page found on Speer's web site. Folks, that is simply a more scientifically accurate description of plating. I can also state with certainty that Federal Champion and Speer Lawman TMJ both use plated bullets, because I have broken down samples of both of these commercial ammunitions.
Finally, I've chronographed my loads and found that with the produced velocities corresponded with data for jacketed bullets and NOT with data for lead bullets. While I don't have any means of measuring produced pressures my training in Practical Physics indicates that plated bullets should produced pressures will also correspond with the data for jacketed bullets. Think about it, a copper Jacket can be expected to produce the same level of friction in a barrel as good layer of copper plating, so why would anyone ever consider that using data developed for a lead bullet to produce results correspond to a plated bullet.
The bottomline is this, load to the maximum recommended velocity for the bullet you are loading with using data derived from that for jacketed bullets and leave the data for lead bullets for lead bullets. According to Speer it is possible to "squib" a plated or jacketed bullet if too light of a powder charge is used and in general data for lead bullets trends to lighter charges than data for jacketed bullets. When I'm using plated bullets I'll use interpolation to determine an estimated "maximum" charge for the 1200 fps max limit normally recommended and regard that as the maximum, even if it's actually a mid range charge for a jacketed bullet. I am also a believer in starting low and working up and have found from experience that a sample load of just 5 or 10 rounds really isn't adequate to determine anything beyond relative velocity. There is a hint there that any new load should be at least 25 to 30 rounds so you can get a good indication of accuracy and function.