I would highly recommend clearing For Masters Only before attempting this one. Even then I was about 100 off at first XD. That came down quickly once I hit on the right idea for how to fetch the last couple of block you need to open the middle.
I'm still not super convinced this is optimal. There are just so many possibilities it feels like there could be more somewhere.
My first idea was the correct one (after a little optimization) There is an interesting structure on the way to the solution, but the rest of the level is not an effective use of space.