During my Holidays, I spent two days with spirit bonding and in the end, I had about 160 Materia II-IV to insert. 45% chance, 19% chance, 11% chance, 7% chance. From the 160 I used, was able to insert FIVE Materia to improve my DOH. The rest, worth several millions of GIL, were destroyed. Plus the mats (and shards) I had to gather to craft the 160 items in HQ. The chances for overmelding are a joke especially when you need to heavily overmeld in order to craft 3 star recpipes.