Jacob,
I have this same problem. I followed your tutorial (which is very good) but my landscape is black. After about 30-40 min I found out where “weight preview” is and changed as you mentioned (I guessed on the numbers) but nothing changed. I’m super new to unreal. It looks like no material layers came in as with yours. I’m not sure how to put those in. I’m sure I will figure it out eventually but wanted to mention that it did not work as in your video.
Thank you,
Brave