PS sounds good at first but when you think about it there are a few issues that come up:
1) Any plots used for this would count against a player's plot limit.
2) WE and Voxel are available in PS but not in main and people may be tempted to use them to complete tasks.
3) 75x75 is a pretty large area for a tutorial. In my three plots I used every single space available to make a checker-hedron, a pretty sweet 3D Maze, and the world's first hot water ice skating rink. But to use such a large space to make a small hut or a couple of trees while leaving the rest empty seems odd.
Only the first point is likely to be of any real consequence. The other two popped into my head and, although I can't see any real problems with them, I can't completely dismiss them. Just feels like there's something legit I thought of that made me think of those but now I can't recall it so I'm leaving them up to let others explore their potential.