Best Exercises for Lateral Deltoid Width and V Taper

I really want to widen my frame and get that classic V taper look. I have been doing standard side raises with dumbbells but I feel like I am mostly using my traps instead of my lateral delts. It is quite frustrating as I want that capped shoulder look.

I have tried doing them seated and also using cables for constant tension. Are there any secret exercises or variations that worked for you? I am also wondering if I should be doing higher reps for shoulders since they seem to respond well to metabolic stress.

I am from Manchester and my gym has a decent selection of machines, but I prefer free weights if possible. Any advice on form or specific movements to target the side of the shoulder would be greatly appreciated by this lass!