I would incorporate some Pause Squats sometime at the beginning or middle of the week. You could also do some Box Jumps right after a set of regular squats (either front or back). Try to do those jumps from a full depth squat. You could also do some Squat Jumps with really light weight at the beginning or end of a training session.
As far as the depth jumps, I've never done them and I've never seen anyone do them to work on speed so I can't comment on that.
The main thing is just to focus on accelerating out out of the bottom of every squat you do, no matter how slow or fast it may be compared to all the European lifters you see on the internet.