I use the solo cup.method as well but it's 2 cups - 1 clear with lid and 1 solo.
Make drainage the bottom of the clear cup and pack down the medium tight made up of 30% Perlite, 20% Ocean Forrest and 50% Coco Coir.
The lid acts as a moisture retainer and I also use plastic wrap (this time I used the thin clear plastic produce bags) and fashion it so it wraps around the lid as well as hanging.over the lid as I tape it down.
The bonus of the lid is that it acts as support to the cutting since the majority of my cuttings were long and the majority of the cutting is outside the cup.
Forgot to mention that the lid and plastic "wrap" around the lid top prevents pesky Fungus Gmats from getting in oh and I actually "punch" the cutting into the lid of the (pre-filled) cup just like a straw.
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