My hair really needs medium weight conditioners. I currently use the medium weight conditioner by Pattern, but I'll be switching over to the Alikay Naturals Caribbean coconut milk conditioner soon just because I'm running out and wanted to try something else. The Pattern conditioner has good slip and smells nice, even as a medium weight conditioner, it's still too light for my hair. Pattern does have a lightweight conditioner too, but it has coconut in it (just in case you're allergic to coconut). I checked the ingredients and they look good and safe! There is hydrolyzed vegetable protein in the medium weight conditioner, it's more than halfway down the list so it's very gentle, and NO protein in the lightweight conditioner.

As for leave-ins, I have been using the Aveda nutriplenish leave-in. It's definitely lightweight! I tend to use like 10 sprays on my hands because I need a lot of leave-in for my curls. You could probably just do 2 sprays on your hands and rake it through your hair. Also, since you said sebum is really good for your curls, you can do 3-4 drops of jojoba oil in your hands and do the "praying hands" method by putting your palms together and gently going over the length of your hair. Jojoba oil is really close to our natural sebum, and it will help lock in moisture without weighing down your hair. It also adds shine and protects your ends!

Hope this helps!