To make your necklace wee-balanced as Yin and Yan, those classic Goro's items are your best choice.
If you are worried about the water, the Chains are recommended instead of the Leather Cord.
The signature goro's setup like this would be a great idea for you to start your goro's journey. You may add the Gold Tip Feather and the Silver Wheel, Leather Cord and Beads for upgrading to the Takuya Kimura Setup too!
・Small Cornered Chain with Eagle Hook
・Gold Top Feather (XL)
・Heart Wheel Feather (L) ×2
・Silver Wheel with K18 Gold
・K18 Gold Sun Metal