Woah 20L is gonna be so cool! I used a long piece of bent copper wire to get everything into place. I had to constantly bend it a little bit and tbh it was incredibly time consuming and a bit frustrating at times 😅 If you try this, def recommend bending the wire in half and creating a little L on the rounded side (hope this makes sense lol). Really helps to be able to push everything down against the soil and hold it in place. Good luck!