Craig,
You may need to reduce development if using TMY, Tri-X, or HP5 to avoid blocking up highlights or losing separation in the highlights. I'll probably have a penalty flag thrown for the following comment, but I have done the exact same thing as you have for the exact same reason - an image that required an extreme amount of work in the enlarger to get a good silver print. I sometimes work on the edge of light and trying to make an enlarged negative using traditional methods would have been fraught with frustration for the reasons you describe. My solution in those cases was to do a high-resolution scan of the silver print and make a digital negative for printing in Pt/Pd. This approach avoids all of the pitfalls of losing shadows, blowing out highlights, or losing highlight separation in the copy neg. Forum moderators can banish me to the hybrid forum, but I look at digital as just another tool to get the final Pt/Pd print regardless of it's source. I still shoot film for most all of my own work, but the only thing that really matters is the final print. Whether it comes from a film or a digital negative is irrelevant in my opinion.
Bob Herbst