I'm 6'5", around 230lb, and have a longish torso. A little more body fat % than I'd like. I don't know my chest measurement, but I like XL-long shirts.
I wear XL plates, not sure who the actual manufacturer is, but they're an older version of the velocity systems API-BZ.
They're thin enough I can actually fit them into an old Eagle BALCS low profile armor carrier over the soft armor (size large, it's an edge to edge fit and takes some wrangling to get them in or out).
I've found that, worn like this, they sometimes ride up and poke me in the neck getting in or out of cars. I've been considering trying out L size plates.
That said, the Eagle carrier rides a little lower than I like. I need to throw the plates in my PC and give it a try, see how it compares and if it's the carrier or the plate size causing it.
YMMV