OK, scratch all of the above post. I think that's sorted (what a bitch to code, wow). The dev used a completely different dialogue location for the "thinking" parts than all the other dialogue which is very odd but whatever. Now that it's discovered I replicated and negated as needed for the Sancho dialogue box / OEM dialogue box toggle to work as I intended.
Sorry for the delays but you know I want my stuff bulletproof. I'm moving forward in the testing. If I don't find anything else serious I'll compile it, grab a quick lunch, then test those compiles on 2 or 3 virgin testing systems. If that passes I upload the links and we're done.