Paella rice

I'm serving paella to 15 people in a couple of days and I just discovered I don't have nearly enough official Paella (i.e. Bomba) rice. I've read the many posts by folks that have used other short/medium grain rices that have worked fine, usually Arborio. Unfortunately, I live in a rural area and the only rice available is the usual short grain Japanese rice. (And long grain Basmati which is definitely a no-go)

I remember reading or hearing about a restaurant in northern California that specializes in using locally sourced ingredients. Not wanting to import rice from Spain, they use local Japanese "sticky" rice for their Paella, but they processed it a bit first, but I don't recall the specifics.

I'm guessing a good rinsing to remove starch, but I thought there was more to it than just a rinse. Have any of you heard of this or recall the details of their process?