My suggestion to the OP is that if you're going to carry a striker fired gun AIWB a safety is a good idea.
I understand both sides of the never ending dispute but IMHO most AIWB 'accidents' occur during re-holstering and most don't have anything to do with your trigger finger being on the trigger. Most of the time it happens because something gets caught between the trigger and trigger guard (i.e. portion of your shirt, jacket, jacket toggle, or even a rock if you go prone…I've seen it happen with a hammer fired gun).
With a hammer fired gun we always teach our students to keep their thumb on the back of the hammer when re-holstering because IF there is an object obstructing the trigger/trigger guard your thumb will feel the rearward movement of the hammer telling the shooter to stop.
Obviously on a striker fired gun you get no notice until you get the worst surprise of your life. Again, just my opinion but, even if your holster rubs the safety off to fire after your gun is in your holster, it's already in there so no harm no foul. That's what all of the other internal safeties are for.
I would agree that if you come from a 1911/Browning Hi power background it is a much easier transition…BUT by the same token if you're 3 months into your shooting experience it's a perfect time to learn since you haven't developed any habits (good or bad) to re-train.
The worst thing that can happen if you learn to shoot with a thumb safety and you decide to get another gun that doesn't have one down the road, is your thumb will naturally sweep a safety that isn't there…no big deal. It won't slow your speed. I had to make that exact transition when our team transitioned from the Hi-power to a Glock after almost 10 yrs of carrying a Hi power. Now I'm issued a Sig 229 and it required the most amount of change (which wasn't much) because the slide release/lock is where a thumb safety would be and it wouldn't allow the slide to lock back after the last shot. I changed my grip to move my thumb over a few mm and problem solved.
The last 'con' of a thumb safety that is brought up often is your thumb could inadvertently put the gun back on safe as you shoot. My view on that is they're probably shooting by tucking their thumbs vs. a two thumbs forward grip. If you tuck your thumbs it naturally places your thumb underneath the safety and upon recoil that same thumb has the tendency to push the safety up. When you grip the gun with both thumbs forward your right thumb (if you're a right handed shooter) should rest on top of the safety so when the gun recoils there's no way to put it back on safe (assuming your gun is in proper working order otherwise we can 'what if' this to death). Here's good vid that you might have already seen that talks about a bunch of stuff but shows thumb placement better than I can explain it:
https://www.youtube.com/watch?v=ysa50-plo48
One final thought/example… It's easy to quarter back this example to death…I get that, but stick with me…a LEO buddy of mine who has a deep SF background and 15 yrs as a LEO, purchased a new holster for his off-duty Glock earlier this year. He'd been carrying AIWB for years with his Sig (probably in the military before that). As he was getting accustomed to his new holster, he was moving it around getting it adjusted correctly, and since it was new it was tight. Well he also had his cover garment on, and something got caught in his trigger and in the course of all the tugging and moving it went off. The round went through part of his ab, his scrotum, through his thigh, and came out of his knee. He lived. He's still recovering but there's no guarantee he'll make it back to full duty. His knee is pretty screwed up.
There are obviously a ton of things this guy could have done to avoid this…#1 being the damn gun shouldn't have been loaded in the first place. And maybe a thumb safety wouldn't have helped at all, BUT maybe it could have.
I give this example not to pick apart but as food for thought of the risks of AIWB carry and how even an experienced operator can make a huge mistake. In my job we're taught early on that the job is dangerous and many ways to manage those risks. IMHO, a safety on a striker fired gun carried AIWB is one way to manage a potential risk. It doesn't eliminate them...accidents still happen and whether it's operator error or mechanical the outcome is still the same. I'm not sure if this is true or not, mostly because it hasn't happen to me in 22 yrs carrying a gun for a living…knock on wood…but the saying goes that at some point in your firearms experience you're going to have an AD/ND/UD or whatever the most 'correct' term is for the same thing. If/when it happens; I don't want it to be like my co-worker.
Regardless of which way you go always manage your risks and train hard. Sorry this was long winded.
