Do you print or scan the negs? IME, Pyrocat-HD negatives almost always appear thin, but print very easily. My experience with Microdol-X is that it cuts film speed worse than Rodinal, and difficult to obtain decent contrast(TX/MicroX). If you want consistantly more contrast, extend the dev time in PC-HD, or same time and warmer temp. Either way, you need to up the agitation as well. Vigorous agitation and more often rather than lazy inversions . One full minute of vigorous inversions followed by two rapid inverts every 30 seconds or even 15 secs. You can even change your dilution ratio, and will get different results, no need to get locked down on one dilution. Experiment with what you already have before investing in new.