I'm 4a/b - and I LOVE Oyin. My hair's a good bit longer than yours, and I cowash only - so with that in mind - this is what I've used from them.....
1) Whipped Pudding - hair, skin, everything - this stuff is wonderful. I use it as part gel, part sealer on damp hair.
2) Honey Hemp conditioner - the best leave-in EVER. My hair SOAKS up conditioner, so I don't use it to condition or to wash (my precious!) but I do use it to soften my hair to make combing easier.
3) Burnt Sugar - the stuff I most LIKELY use the most, as I use little dabs of it (plus a doorag) all week to keep my style slick and tight without pulling on my hair.
4) Shine & Define - I haven't quite figured out a use for this yet - I think as my hair gets longer, and I can wear it out again, this might be nice to work through my hair....
5) I've just started using the Greg Juice again, as I did NOT like it on my loose hair - but I'm using it as a misting conditioner for my twisted hair - and it pretty good. This, I most likely won't buy again, though.
6) Grand Poo Bar - used it once, didn't like it, decided to definitely stick to cowashing only.