If your doing 15 10 5 or 12 10 8 or whatever your regular rep range is, I would keep side lateral raises at 15-8 reps, if you can microload by adding .5kg plates or extra spinlocks(.25kgs ea) thats even better.
The way I do them is standing leaning forward by about 25-30 degrees, elbows bent at only 10 degrees, and I raise my arms out to my sides and back down to my sides without touching legs as to keep tension on the delts, I also make sure I do extend my arms out at 90degrees from my body which is hard, and dont bring them above 90 degrees from the floor, and as they come up I slightly tilt the front of the DBs down so my pinkies are just a little higher than my thumbs, this is the best way to isolate the side delts, done right this exercise is an ego breaker as you will need to drop weight to keep your arms on the correct plane of motion (to your sides which is furthur back than you think) but it will allow growth of your side delts without overpowering front delts which would otherwise dwarf your side delts.
Another reason why you will need to drop weight is that by not bringing the DBs infront of your body you are keeping constant tension on them so its a real set not just 8-15 sets of 1 rep with no break inbetween.