2a,5b,3c,214axx214D are all great pokes vrs him that can lead to knockdowns. The only thing imo you need to watch out for is Jins 5c, into his 5D. You get hit with that and you can kiss 75% or more of you life bar goodbye. Also when your waking him up watchout for his ice spike move it has invincibility can lead into combos iirc but when baited like anyother DP style move has horrible recovery. This is Day one for me but im sure the more experienced people can help you out.
I just spent 10 hours doing the ragna vs Jin matchup with 2 very good GG players in town. Its not a bad matchup you just have to learn through experience.