Whether cutting black-eyed or purple hull peas, you definitely want to lean towards a cylinder combine, even if desicating them.
Settings required for field peas of these types requires extremely wide concave gaps and very slow cylinder speeds to prevent "juicing" (smashing) the stems and cracking the peas. If your peas are anything like the ones at harvest here, the stems are green as a gourd (reminds me of watermelon or cucumber vines) and the pods so dry they snap right open when just looking at them. Because of these conditions, the twisting effect created by axial type rotor combines juices the heck out of the vines and plugs over their sieves. A cylinder is more capable of running much slower with a much wider concave gap due to its higher inertia cylinder(s), making them much more effective in these types of conditions (even in green stem soy beans). They have less juicing and higher grain quality. When harvesting the peas in our area, it looks like manure falling out the back of a combine. All peas in my area are cut with either Deere cylinder machines or lexions. Any axial type combine owner has at least an old conventional combine for their peas.