Bos19, you seem to want to make good decisions and get it right without breaking the back. Admirable. What you need is experience, and when yo start carrying, it comes with time. To address the issues I see here. Remember that free advice is often worth less than what you paid for it.
First, SIG had teething problems with the first P365s. It happens. They seemed to have gotten that worked out, and if I was going to carry one, I wouldn't hesitate after putting a couple of hundred rounds downrange to prove that PARTICULAR SIG P365 was good to go. Besides, its fun to burn powder and make noise.
Second, most of us have more hand than gun when it comes to tiny pistols. Its not a problem, you just have to get the technique down. I don't know ANYBODY that carries a Kel Tec P3AT or Ruger LCP that can get 4 fingers on that grip. If you need a gun that small, the answer is get a hold of it and shoot the snot out of it until you are proficient. Instruction is a very good thing here...
Third, you CAN conceal a large service or compact pistol. I'm 6'4" and 225 lbs, and I can hide a G27 with +2 extended base pad just fine in
this. (with the +2 it is almost exactly the same butt length as the G19) I carry this way to church in slacks and a knit shirt during the hottest days of summer. Nobody knows its there, and it makes our pastor happy knowing its there. (we're close) If you did this with a G43, G43X of even a G48, it'd be even easier for you.
Fourth, my recommendation is to find a handgun that works for you, and dress around it. If you are to carry concealed most\all of the time, you will have to make some concessions sometimes. Maybe you'll find a J frame airweight works best for you when you can't wear a jacket. There are times I go somewhere in jeans and a t shirt with a dark broadcloth shirt covering my OWB holster and aforementioned G27.
It sounds like you're still going through "new to carry" syndrome. We've all been there. You're afraid you're always printing, scared someone will see, always tempted to touch or adjust the pistol. It will pass, and you'll be amazed how well you're going.