I'd say you did good. I wouldn't worry much about it's capacity. Best part of a hydraulic winch is it won't hurt itself. If you hitch it to a load it won't pull, it simply won't pull. No worries.
I had a 10K Milemarker hydraulic that I used on a Jeep til it burned in my shop fire. Only thing I didn't like was it's speed. But it would pull all day with no worries.