I've made some visual improvements in my shoulders lately in the last 2-3 months doing a few things.
1) The rear delts give a lot of 'width' to your physique, just like the medial delts. So I would definitely make sure to nail those
2) Medial delts, my favorite movements are basically the partial ROM laterals you're talking about in the OP. I hit the Partials for 4 sets of 30 one day of the week. My next delt day, I hit 4 sets of regular Laterals for 10 + 20 partials at the end of each set. Really burns my shoulder.
3) I like to do high rep DB presses after hitting rear/medial delts. Like sets of 15+