Worked for me under both Tutu and ToB. I made a point of checking before posting.
Incidentally, I also found that there's a good reason why the Readme says the GUI should be installed after Tutu, or more specifically, if using the GUI with ToB, why TutuGUI should be completely uninstalled and then reinstalled once Tutu's done setting itself up. You get some weird combinations there with the main menu screen and the loading screens. Reinstalling the mod doesn't help in that particular situation, either.
Just so we're both clear on my current installation, though:
BG1 (original 5 disk version) + TotSC (patched to US5512) (fresh install)
SoA (original 4 disk version) + ToB (patched to 26498) (fresh install)
the BG2 paperdoll fix
a single .itm scroll with a scribe-able Dimension Door on it (I'm a mage junkie, but haven't made use of the scroll yet)
BG1Tutu v6 (I was Tutu-ing until encountering the bug in the Nashkel Mine with Mulahey's scroll and couldn't progress to Chapter 3, then uninstalled it to putter around in SoA/ToB for a bit, still with the GUI installed)
TutuGUI v 1.31 (started using this at v 1.2, completely uninstalled it and removed all associated folders when v 1.3 came out, then patched that with the service pack, then completely uninstalled the SP and then the GUI itself, and deleted all associated folders to install v 1.31)
This gist of it is that my installation had changed a fair bit, but I've kept things as distinct as possible.