Im not a soft start expert or anything but I did one on a 4 slot like 5-6 years ago and it wasn't too bad. Unfortunately the print I marked up when doing it is still at that job and the company I work for does not service that job. And my clip board with my pull sheets I've made are on a job I can't get to for a little while. But I can look through what I have for prints and see if I have anything helpful. If I remember correctly you won't need to add a "motor up to speed" relay cuz it's built into the dover wiring already

Pm me your email and I can also send you a picture of a print I have on my phone