Rep schemes that I use with all my explosive exercises (muscle snatches, plyo pushups, jump squats, clean and snatch pulls, speed bench press, jump shrugs, push presses, and push jerks are my favorites) are 3 x 5, 4 x 4, and 5 x 3. But I do these at the beginning of a fully-body workout.
If you use an upper-/lower- body split, you can fit more sets in. You could use a set-and- rep scheme 10-12 x 2-3. If your form really needs work, you could do 15 - 20 x 2 - 3 reps with a very light weight for speed-squats and -bench presses (only; 20 to 30% for the OLs would be a joke!).
A good guide on speed training is provided by Elite Fitness Systems. Or you can just refer to Dave Tate’s articles on here.
There are no rules as to when you use straps. Personally, I don’t need them with low-rep work and I have a very strong hook grip. I need them with high rep (>8) work.
As you have read above, I don’t include highly technical lifts in my speed work as a) my form is abysmal and b) (I don’t say this to brag) I have too much muscle mass in the shoulder girdle and arms to catch the bar in the snatch and power clean.
If you have trouble with snatches and cleans, try muscle snatches. These don’t have a catch. It’s a combination of a deadlift, high pull, and 1/4 overhead press. They work the entire body too; you will probably feel destroyed after 5 sets of these with a high intensity. Try some of the other ones I mentioned too. Let us know how it works.