Place and raise gozas, then place curtain and chop gozas.
Raising/lowering individual panels involves lowering a goza after the curtain is placed to 'break'* the curtain.
Individual panels can then be moved up or down, so long as they do not get re-aligned on the same z-axis height.
*Be careful with broken multi-tile decorations; chopping a piece before all of the pieces are re-aligned** will destroy a piece, thereby removing the ability to re-deed the item. [The remaining pieces can still be moved up or down in this case until they are individually chopped-destroyed.]
**You will know when it is re-aligned when every individual piece gives a 'you cannot raise/lower this item'