Looks like the OP has not logged back in, or has not responded to posts to his/her thread.
Anyway, when you get back, Mallen65, this is for you:
Go to your local Walmart and buy a box each of FMJ ammo (full metal jacket, aka "ball") for range testing. Walmart almost always carries Remington and Winchester white box. These are normally sold in boxes of 50 rounds each.
Then get a box each of any other brand they got, as long as it is jacketted ammo. You may want to get a box of each brand of JHP (jacketted hollow point, or defensinve ammo). You may find that these are only sold in boxes of 20 rounds each, and will cost more.
Then try to visit a couple of dedicated sporting-goods or gun stores in your area. Don't buy ammo you already own, but basically follow the same plan on what to buy.
You will find this is going to cost a bit, that's OK. Look at it this way: your life is worth it, and is worth the investement in learning what works best for you to save your life. Think of it as tuition. A one-time expense.
Then, go to the range, with a variety of targets. Shoot slowly, taking your time. As much as possible, make sure you are always aiming at the same spot (POA or Point of Aim), then make notes on where the holes appear (POI or Point of Impact). If shooting watermelons or phone books, etc., also make notes on what the target looked like after a direct hit to the center, a glancing hit, etc. Also make notes on things like was there a cloud of smoke after the shot, did it hurt you hand to shoot it, was it louder than other kinds of ammo, and so on. Also look at the spent brass (the ejected cases)...do they look clean or coated in black carbonized residue. Cleaner-looking brass means this ammo is (generally) cleaner to shoot in your Glock, meaning less crud left behind in your gun that you need to now clean out. Write everything down.
When you get home, review your notes. You may find your answers right there. This will usually suffice for the casual shooter wanting to take personal responsibility for his own (or her own) protection.
It is possible, and many do, take this a step further, and try the more expensive defensive ammo. By all means, try this at least once. Remember: it is your own life you are protecting, and it is well worth the expense in research to find out what works best for you and your gun.
It may also help if you have someone already familiar with handguns to go out shooting with you, this provides a second opinion, but in the end it is your decision alone.
Some tips I follow (and these apply to me and may not apply to anyone else, but I share them just the same):
1. I NEVER shoot bare lead ammo thru my Glock. It affects the barrel, and invalidates the warranty.
2. I stay away from ammo in steel or varnished steel cases (Wolf, Tula, and so on). I do not like the hardness of the steel eventually chewing up my extractor claw, and I absolutely hate the vaporized varnish contaminating my Glock.
3. I avoid aluminum-cased ammo (Blazer) because I cannot reuse the cases and they become trash.
I hope this helps.