Hello -
I installed EasyTutu (ToB version) on my computer that has BG no-TotSC.
I played and made some savegames.
I am now upgrading my computer to have TotSC.
What is the best way to make TotSC available to Tutu? Run EasyTutu again?
Yes, you'll need to reinstall EasyTutu so that it can grab the TotSC-specific game resources.
If I run EasyTutu again, will my existing Tutu savegames be compatible from the no-TotSC install to the TotSC install?
Almost, but not quite. The main problem you have is that your current savegame has a TotSC-less world map burned right into it. Consequently, no amount of traveling around will cause either Ulgoth's Beard or Durlag's Tower to appear on the map.
Unfortunately, you'll need to restart if you want to experience the TotSC content.