Tried to make a setup and I think this one is pretty good. From on top of the door to Ice Ruins West:
1. Line up with the middle of the door and stand on its edge
2. Line up with this spot https://prnt.sc/kcKjANfPvnGh
3. Jump in place, and at the apex start holding down. Jump again and release L when the L reticle passes the top of the door
4. Walk back until this rock is just touching the left side of the screen https://prnt.sc/MDiku3Ib37Q
5. Mash B for a jump and then morph quickly after you get it