Glad that someone actually make it,
And I think I know why I never success before, cauz I just focus on to make jimmy bigger, and never actually try it with the other student character.
And I try it, and like you say it is quite unstable, sometimes when the larger student interact (like say hi, etc) with people or Me (jimmy), sometimes it will just shrink back to its original size
But for the apple that I change with crablesnitch, where I just edit the scale for the nitrishape, it really stable even if I interact with it, like grab the apple crablesnitch or throw it, it never going small
But when I just scale the ninode like the picture below, not the nitrishape, the apple just unstable, it sure it is big when I don't interact with it, but it will gone when I grab it
For the character model if we just scale the nitrishape it just don't make the character larger at all, but we need to scale the dummy to get a larger character but it is unstable somehow
But I think this is good enough already