BG1(+TotSC) full install is needed for obvious reasons. But...
Maybe, just maybe you could dump the movies from install and still have a working conversion. If you do this, I assume you'll also have to disable the movies in BG2 "baldur.ini".
As for BG2...
I made a minimum ("compact") installation, without ToB. To run Tutu conversion on this, your BG2 CD2 has to be in drive. It *seems* to work. But, keep in mind that I only checked that first map after Gorion/Sarevok fight and Friendly Arm Inn. Encounters were fine, no crashes.
One would think that even the minimum install would copy the *entire* engine to the disk, leaving various items/maps/movies/non-engine files on CDs 2-4. <-- Qualifying for Tutu requirements?
Hmmm... I checked tutu's log file and there were a bunch of "failed"/"resource not found" messages. I take it as a bad sign. heh :-)
.....................................
Since the following might be "minimum install" related and I'm too lazy to make a new thread:
As I recall, wasn't there a movie when you enter "Friendly Arm Inn" in BG1? I don't mean the one when you enter the *map* (this one played ok). I mean the one where you climb the stairs to the inn - it didn't play.
So, is it a Tutu's or Lu-Tze's bug? :-)
One more thing...
That first map (CHP1), after Gorion fight... The creature spawns seem weird:
I cleared the map from those Gibbies and Wolfies. Because of those 2 Dread Wolfs (2x 650 xp), I leveled up (Thief - Sharpshooter kit mod). And then, on the same map (no resting or leaving the map), I encountered more Gibbies and Wolfies (and those 2 Dread Wolfs) in the same places. In no time, with lots of running and "arrowing" and two haste potions (i took/stole one from Imoen and one from Xzar before ditching them) I reached level 4 (!). I'm one of those players that linger on the map until it's 100% explored and clean from all "dirt". :-) But, this was a "neverending story"...
I don't remember it like this from BG1, so I take it as a Tutu thing.