I'm about to start to learn how to shoot IDPA style, using my Glock G17 and G34 Production SSP. I'm all geared up, but want to know more about ammo loads. I currently have the Vanek Classic Trigger kit on both the Glocks and a Wolff 13lb recoil spring. What's the best heads, power factor etc to have a good shooting pistol out of a Glock? TIA!