Or just wrap the solo cup around a huge girdled branch, and let it root out before you cut it... And melt it back together so there are no "holes on side" that break the rule.
Last time I even used solo cups before now was for an air layering experiment a few years ago. One of my clones was already 3-4 ft tall, before it even rooted out the cup. I let the clones fill the coco filled cups before completely disconnecting from the mother plant. I could have just used the cups to start with, and not a rooter plug covered in cling wrap.
My seedlings might be weak sometimes (especially this winter!) but my solo cup clones are the biggest in the world that I've ever seen. I could take one off my current mother plant right now if you guy's still want to play that way.