My advice to you would be to keep it simple.
Squats and a hanmstring movement, bench and a upper body pulling movement, after the rest of your workout on high-intensity running days. Use sub-max weights, 5-10 reps, and maintain good form. Maybe 1-3 times per week, depending on the rest of your work. Remember that weights are a general stimulus and must never take too much of your energy to take away from the sprints.
A good dose of low intensity core and abdominal training throughout your week will be good, as well.
Don’t worry too much about your technique in the sprints, as your strength grows and your training age increases, the techinque will sort itself out, as long as you are staying relaxed.