Satsuma gets good reviews.

how many years has it dropped?

Santa Rosa was my first plum and I had no other prunus and it set fruit well. I have pluots now in addition...

I think it is self fertile...

I have used my Santa Rosa's as a pollinator for my Satsuma's for 35 years. The pair have worked nicely for me. The plums are both good...albeit very different tasting. Santa Rosa is tart, and Satsuma is very sweet and "fleshy". They are good low-chill fruits.

Mine gets pollinated by Krauter Vesuvious myrobalan plum. I know this for a fact because I have several red-leaf hybrids between Santa Rosa plum (seed parent) X K.V plum (pollen parent).

Mariposa plum also gets pollinated by KV plum.

Mine (in SoCal) was self-fertilie.

I use Santa Rosa to pollinate my AU Rubrum. They both bloom at the same time and pollinate each other. I have so much fruit on both trees that I have to use board supports.

I think I'm just going to get both a statsuma and a shiro. I'm not sure I'll be able to find room to plant both but I figured that I could, at the very least, graft them