Mid cage MTB RD is the way to go for SRAM 10-speed. You only need the long cage for triples. Might even get away with short cage if you're not going full dinner plate on the big sprocket.
What he said, plus the 36T sprocket option because why not? Compared with the old 6-speed touring blocks, which were fine, the jumps on a 12-36 10-speed are smaller on the middle 6 and you get 2 extra gears at each end
Mid cage MTB RD is the way to go for SRAM 10-speed. You only need the long cage for triples. Might even get away with short cage if you're not going full dinner plate on the big sprocket.