Sorry if I confused your post or my reply was confusing, but I did not mean to imply that you use more finger when shooting one handed, just that I tend to use more finger when shooting one handed which is what I was assuming and from your description would be more like your finger placement. So yes, I do get a touch more finger on the trigger when shooting one handed which is probably more like your normal finger placement that you describe. At no point do I ever get into the first grove or first joint on the trigger.
I don't worry about "the wall" in the majority of my shooting. I only focus on that if I am going for extreme precision, generally seen at very long distance or for up close say on one hole type precision.If you press the trigger straight back, why does it make sense to bifurcate the press into two (or more) parts, with the wall as an intermediate stop, since the wall doesn't fire the shot?
I do indeed find a notable difference in the trigger stroke and therefore the reason why I break it up. I am somewhat nitpicking and some might think I am a bit crazy, but the results for myself are clear, so bear with me as I try to explain what I am feeling / doing. I am pretty far out on my trigger finger this gets me more to the tip and provides for better tactile feedback. Keeping this in mind, when I pull a Glock trigger I feel 3 distinct phases with 2 separate engagements. Now I am not talking about grit or crunchiness aka creep, but two actual engagement points. When I pull the Glock trigger from its forward most position you have a very easy pull right up to the first engagement point. This first engagement point is where the disconnect of the trigger bar hits the firing pin safety and is about midway between the very forward position and "the wall". I can distinctly feel that firing pin safety hiccup and see it in my sights.
Once the trigger bar disconnect contacts the firing pin safety the trigger drag increases or pull weight increases as the firing pin safety and spring is being compressed and pushed up into the slide. From this point we hit "the wall" and we have the normal pressure from the rear of the trigger bar contacting the connector and the rear of the cruciform giving the firing pin more compression, until finally the connector forces down the trigger bar / cruciform into the release notch of the trigger housing mechanism and releasing the striker. When dry firing the release of the striker and the spring tension snapping it forward, we can see a notable "boing" or "twang" and slight shift or movement in the slide which is also an influence on the weapon as we fire. We just don't notice that when live firing, but it exists as an influence on the weapon and can influence accuracy but I am digressing a bit.
So for myself I do see a noted difference in reading my sights in my sight alignment / picture between the two different pull types. Even with a well practiced and stable platform using the all the way from the front and single pull method I see an ever so slight increase in movement or inconsistency in the "wobble zone" and I see that happen at the firing pin safety engagement and again as I hit "the wall" and continue through to break point. So yes when I shoot for very long distance or just extreme precision, I stay very relaxed as I present. I get rid of the pre-travel and the felt decompression of the firing pin safety until I hit "the wall". From here, this is really my starting point with everything, sight alignment, sight picture breathing. I exhale to get the body calm while getting an alignment / picture and I refine the "wobble zone". This is where I start the pull with steady and consistent rearward pressure. I see a noticeable decrease of movement in my sights as I don't hit "stages" during the pull and my wobble zone stays smaller.
I am not saying that this works for everyone but at least for myself when I shoot long distance especially (which is fairly regular), I can clearly see the difference in my own performance with hits on target. As I sit here now and play with the SIRT, not quite exactly the same trigger feeling but close, I also see a slight inconsistency when starting from the front as opposed to taking out the pre-travel first. The laser reflects the difference that my hands feel and eyes see.
Bottom line is there is not much room for me to offer critique to great shooters like yourself and OAK especially on a forum. Also nothing is going to work the same for everyone and I do know quite a few people from both camps that perform well with either method. Oddly enough I come from a revolver carrying era into a DA/SA decade and a half, so one might think I might like more finger and one consistent pull technique, which I did, but now find myself getting away from that if / when I need extreme precision. What works for me right now, I can say with 100% confidence that I hope a year from now I can then say that I have tweaked something to continue to improve myself. Maybe I just need to start sucking less, or take up golf again, so I can have something new to over analyze.