Can you not just merge a copy of all visible layers into a target layer? This preserves the original SO layers, thereby non destructive..
(Select the uppermost layer > Shift + Option + Command + E)
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I followed the tutorial....
Original
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Comic Book Effect
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Layers panel with original SO layers (Under Effect Group) and a target layer
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The target layer can be moved wherever needed.
Also as discussed in the tutorial, you can add new images to the PSB file (SO), save and then create a new target layer.......all in one document. You can create all of your frames in one document. Do your "erasing" on the target layers.
Second image (same document)
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Layers panel with second image (SO) converted to target layer.
All I did was drag and drop the second image into the (SO) PSB file and save.
The effects are automatically added to the new image upon save. You can make changes to the effects if you like (per the vid tut)
Back in the original file (PSD) Create a new target layer as described above. Edit or erase on the target layer.
You can do this as many times as you wish!!!
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PSB files layers panel...
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