Why mod the flash with an auxiliary sync jack when the hot shoe adapters are so inexpensive?
My flash mod is not for everyone, for just this reason. If you are only using the flash in an off camera mode, then when mounted on a stand, you will need some kind of shoe to physically hold the flash unit in the umbrella adapter. There are many different brands of the adapters on the market. I modify two different models for use with a mini plug or other connector as needed. In addition, I usually suggest adding the safety clip before assembly as a way of preventing cable pullout and relieving the strain on the wire.