Any guide I try to find on this topic just shows you how the process works which I already know. However I can't seem to find any guides on spiritbonding/converting that actually teach you how to do it the most efficiently and which items have high chances to yield specific types. I know there's a speed bonus if its HQ and/or if there's something melded onto an item, but i'd still like to know what are the best ways to spirit bond as well as what items to spirit bond with to increase chances of getting certain types of materia.

Any in depth guides on this?