If you start the script while you have a ring of dueling equipped, the script will unequip the ring of dueling and keep that one in the inventory the entire time the script is running and will withdraw a new one from the bank which it will equip. So one inventory slot is always occupied by the ring of dueling. The ring of dueling is charged btw.
So make sure to start the script without equipping a ring of dueling.
Runecrafting lava runes with pure essence.
Additional info/options: mirror mode, fire tiara, earth talisman, binding necklace, stamina potions, no abbys, no pouches and ring of dueling.
Edit: this seems also be the case even if you do not start the script with a ring of dueling equipped? After a couple of runs it keeps one in the inventory.
Edit 2: now it has 3 rings of dueling in inventory.