Hi, Yes that is true about the grip safeties, the basic reason for them is exactly what you are talking about. Good grip is really important.
I jumped back in to add....
If you do not hold a tight hold and good back up for the semi-autos so they have something to keep them from going backwards, (the buck ) you feel is important. If you (or friend) fail to give good bucking support, there is a chance of it not going back and chambering the next round, the recoil needs to be felt with a stout hold...G
Practice, put hundreds of rounds through it in a slow easy going enviroment.
The safety on the trigger is exposed if not in the holster they make and then the branch pushs on it or someone goes for it. The holster is part of the safe process.
Picture the 1911A1 with the hammer back, that is what the glock is like when ready to go, but the safety on the trigger is there, so if the finger is not on the trigger, they feel that is the best way to go. Similar to carrying your M16 loaded (in chamber) and safety off, with the finger not on the trigger.
Once you have pulled back and released the safety, then you continue to pull through, releasing the trigger before you fire and taking your finger off the trigger puts it back into the safe mode. I like the little longer trigger squeeze, it gives you an area of safety.
Some of the target models have a tighter squeeze(distance not as much slack) and a lighter trigger pull.
But the one you are looking at is pretty much the normal everyday unit.
For you right now I would say the best way to keep it, is with no round in the chamber, that way the hammer is down until you pull the slide back and chamber a round.
Once you get your particular piece (pistol) You will become acquainted with it by shooting, be particulary aware of the length from when you start to touch and pull the trigger, you will feel a short time of no resistance (slack).
You will then meet the resistance and that is when the amount of pressure exerted is what is necessary to complete the process for the trigger to fall and strike the firing pin.
Remember any time you release that pressure and go back to the slack area and then take your finger off the trigger it is in the safe position.
Shoot the regular 9mm parabellum round (Ball M882)for awhile and get used to it, I think that is about the least expensive and what your gun is designed around...
The lighter hotter round (HP) is not what you want to start with takes about 500 to 1000 rounds before it is going to be feeling good to you.
They have already been fired many times and they will come with a target with holes in it to show how well it shoots (pattern).
Good Luck, Regards, Gary