Got it from Virusman. I'm not going to post a direct link, but I'll tell you where it is. For anyone looking for this, consider this an extra step and warning.
Warning from V
don't use it because it is very dangerous: the second toolset overwrites the contents of the temp0 folder with its own module, essentially breaking the first toolset and corrupting the module. Copy&pasting stuff between toolset windows is not possible, so it's not very useful for the risks it brings.
That being said, for my purposes. Which is strictly comparing tilesets. It works perfectly. I'm using this from 2 different installs, ran the patch on my secondary toolset (modifies the toolset exe)
So hopefully I've conveyed the pitfalls. So to find it, go to the list OTR linked above and it's near the bottom, look for the one that says something like,, toolset multi_patch.