Last night I updated the Foliage System (integrated into MSGT following your previous tutorial) succesfully! 
For anyone interested, i just migrated the updated version to my project (to a new folder, I made some changes so I didn’t overwrite the ‘old’ version so I could copy over some blueprints) and then followed the tutorial again (with a little bit reverse engineering) and changed all previous links to the ‘old’ Foliage System to the new Foliage System. The Foliage System works now great… again 
Thanks again for your great work!