But I only wear jeans!
Me too. And I’ve carried up to 1911s and medium frame revolvers. N frame S&Ws in winter time.
Inside waistband allows this.
But I don’t like IWB!
Neither did I at first. Then I a) bought a good IWB holster, b) for a thin, flat, gun, and c) wore jeans a little big. Plus, d) I gave more than a few days’ effort to it.
But that only hides half the gun!
Wear your shirts untucked.
But I hate wearing my shirts untucked!
Me too. Until I got used to it. I had to make that choice to do it and get used to it.
There are plenty of “tuckable” holster that let you tuck your shirt in.
^^^^ ALL of THIS ^^^^
IWB does, indeed, hide half the gun. And that is half the battle in concealed carry.
Comfort? One needs pants with at least two sizes larger waistband. No, they won't stay up if you DON'T have your IWB holster in place UNLESS your belt has a couple extra notches you can take up. Maybe consider owning your "fit" size for when you're not carrying IWB, and the "extra" size when you ARE carrying IWB. And some of us (I'm looking in the mirror here) need to "get real" about what our REAL waist size actually is.
Shirt tail out? Yes, if that will "blend" in with what others are wearing while you are out-and-about, do that. It's easy, and for those of us who live in places where "hot" is the order of the day for way over half the year, it is a very comfortable way to wear a T-shirt (be certain to get a t-shirt with enough length to hang down below your waistline, even if your arms are raised above shoulder height). I like to wear a T-shirt as an undershirt and then wear a casual button up shirt as my outer garment. Depending upon the situation (again, think, "does this blend in with what others are wearing?"), I sometimes wear my outdoorsman style button up shirts unbuttoned over a t-shirt. If going into a store where a bit more concealment is needed, I take a moment to button up.
Shirt tail in? Yes. It can be done. There are the "tuckable" IWB holsters that allow shirt tail in. Just be aware that if the belt "clip" is outside the belt, others who are "aware" can easily spot it. The only times that I've been "made" and anyone mentioned it were with that type of holster when I had my shirt tucked in. For better concealment with a tuckable style IWB holster, use a stiff enough clip that it will work when just hooked to the waistband only and use a belt to camouflage the clip. The clip is still visible to careful observers, but nowhere near as obvious as when the clip is over the belt. Another tip: rather than tucking in your shirt tail as snug as possible, pull it out just enough to provide a neat little "ruffle" around your waistband. For those like me, with a "tactical donut", you might have to be certain that your "tuck in" shirt tail is a bit longer than you'd normally choose in order to have enough extra "tail" to form the "ruffle".
AND, I have a nuclear option. It probably won't work for you skinny guys, but for those of us who are packing a bit of extra weight, this really, really works well: Wear a pair of cutoff jean shorts UNDER your pants. Carry your gun in an OWB holster on a belt threaded through the jean shorts. THEN put on your pants OVER the jean shorts. You'll have to have pants with an even larger waistband to encircle the whole mess, and the appearance is too bulky for skinny guys to pull off. But, hey, you skinny guys can comfortably carry appendix and I cannot. So, there. Fair's fair. What about going to the restroom? LOL. It might sound a bit "kinky", but I cut out the crotch of the jean shorts and put a little "Stop Fray" on the edges to keep my scissor work from causing the material to unravel. As an old man, getting to the urinal "in time" is important to me, and this "trick" keeps the inner jean shorts from slowing me down...

This manner of carry provides total concealment of even a full size handgun, it eliminates any hint of belt clips, and is as accessible as wearing an IWB holster. The jean shorts with a belt threaded through its loops keep the gun/holster stable and right where you put it.