I literally did this puzzle as well two days ago! ...but it was a trying experience.
Both puzzles lost a cap, I assembled them in the wrong spot (hence why the color scheme doesn't match AND the Square-1's Middle layer isn't in the correct spot), and the 3x3 got off-centre mid-gluing.
I'm thinking of redoing it.
(Also, I kept the name but altered it. I call mine the "Half-A'ed R.S.T".)
Just re-sticker the 3x3x3 and the square-1 just do a 3,0 or a -3,0 and then do a y or a y'.
You just made the puzzle a bit herder.