[noylj]

Read your manuals.
Your rounds look fine.
9x19 can be challenging for a newbie.
Unless you are wedded to 115gn for some reason, you will get slightly better accuracy (most of the time) and a bit more bullet bearing surface for maximizing bullet pull using 121-125gn bullets.
I prefer JHP for all my 9x19, 9x21, and .38 Super shooting, but that is me.
Since you are using inert "dummy" rounds to set-up dies (excellent idea, since I always do so and highly recommend it), seating stem, and crimp (though I have, after my first month of reloading back in 1972, always separated those two functions as the bullet is still moving down while the case mouth is closing on the bullet), then use them first to verify the COL that will allow the two or more dummy rounds to fit in the magazine and feed and chamber in the gun. The COL in the manuals is the minimum COL the data applies to and your longer COLs will almost certainly be better.
Also, don't think that the factory loads have an ideal COL. They have to work in all guns. However, they are a good place to start, as you are doing, as long as you branch out from there.
By trying various COLs, from long to short, in your gun using the inert rounds, you will learn the COL range that works with that bullet in that gun. COL is effected by the specific bullet's ogive and meplat, where in the loading cycle the magazine lips release the round, the geometry of the feed ramp, and the geometry of the barrel's chamber. As you can see, the gun makes the COL as much or more than the specific bullet.
Pull a bullet. If you look at the bullet and there is a line all the way around from the case mouth, you have a bit more taper crimp than required.
However, you must learn that your gun will know what it wants and there are no absolutes and your gun is not my gun so what my gun prefers yours may not handle well at all. Your gun may prefer the "tighter" crimp that marks the bullet, though is "damage" could lead to gross inaccuracy in other bullets--particularly thin-plated bullets.
Also, don't load more than 5-10 rounds before going to the range and verifying that they function. Many have gotten so excited they "ripped" off 100 rounds or more and then found that they wouldn't function in the gun and had to go home and pull all the bullets.
You will find with testing that your gun will likely be most accurate at some COL --shooting targets will also indicate if your gun has a preference for taper crimp.
This is also why I recommend buying large batches of bullets if you want to actually develop accurate loads and not just simply plinking loads. You will be amazed at the range in group sizes if you very carefully shoot off a sandbag or machine rest.
In 40 years of reloading, I have found that "best" taper crimp is when I can not see any case mouth flare when looking at the round in front of a well lit white background and when I can not feel any flare when I run my finger down the bullet ogive to the case. This will almost always leave an unmarked bullet.
If you are one who believes in measuring the taper crimp, then aim for 0.380".
There is no such thing as "too much mouth tension" from taper crimping and I have no idea where you read that. Now, if you applied a roll crimp and the case mouth got lodged into the rifling, you could see some high pressure, but there is no way to get excess pressure from a taper crimp. In fact, applying too much taper crimp will cause the case just below the mouth to bulge out and you will lose bullet tension and possibly have a round that won't chamber.
Powder: what do you want your loads to do?
Factory equivalent? Silhouette, WSF, AA7, Power Pistol, and others. Silhouette is my first choice.
Light target loads? 231/HP38, AA2, AA5, N320.
General all-around powder good for almost all pistol rounds except magnums? 231/HP38, but all the fast target powders will be about 100-150fps off top velocity even at max pressure and perform best well under max pressure.
If I was a newbie, the first powder I would buy is 231/HP38. Second would be Silhouette. Third would be either AA2 or AA5 (depending if I wanted to concentrate on accuracy only or accuracy with velocity).
Primers: any of the small pistol primers are more than adequate and I really haven't noticed much velocity or accuracy variation switching around standard SPP. Remingtons are good. I prefer Winchester and Remington myself, but not based on performance.
9x19 is not what I would call an "inherently" accurate round and the guns made for it (except for the S&W M952, possibly) aren't designed for accuracy either.
Do not even think about trimming cases. I have never had a sized 9x19 case that was at max length, much less exceeding max length. These cases that head space on the case mouth need to be as close to max length as possible for minimum head space and maximum accuracy. I actually have gone through and measured a lot of sized cases and set those that are 0.750-0.753" in length aside for when I want to be accurate as possible.
With the .45 Auto, all I shoot are lead bullets and I use the bullet shoulder just touching the lede to minimize head space.