ldms_client version 1.2 is posted. HKCU reading works now, and it turns out I did need to use a wrapper program (REGEDIT.EXE /E and REG.EXE QUERY both behaved strangely for my needs). This inflates the size of the client install, but compromises must be made from time to time.
Version 1.2 also reads the Machine SID, and fixes a bug in version detection introduced by some of the post 8.8 patches.
With this release, my planned feature list is all done for Windows clients, until someone suggests some more features. Failing that, I'll be working on a Mac client next.