As a big guy, you can hide a big gun.
I've heard this said a lot, but I don't think it's always true. I think it depends much more on your shape than your size.
If you're "linebacker big" (relatively muscular, shoulders wider than waist), then sure, go nuts. Your shirts will drape loosely because they're hung off the widest part. Plenty of room under there.
If you're "Santa Claus" big (waist wider than shoulders), the opposite is true. Because you slope outward from the top, no matter how loose your shirt, it will naturally drape against your body, or anything attached to it. Heavier (and thus stiffer) fabrics can help, but aren't very comfortable for a large part of the year around here.
On top of that, if you're bigger in the waist or gut (as I am), your belt line has a much more circular shape than someone of smaller stature (which tends to be more oval-shaped). That means that there are no "flatter" areas around your waist to tuck the grip up against. I can carry a full-sized pistol IWB and be perfectly comfortable, but the butt of the grip is always stuck out away from my body no matter where I place it. It makes a small bump when I stand, but if I bend over or sit down it's quite noticeable.
I've tried a lot of options. I live near and work in some very 2A-restrictive places, including some where, while carry is legal, if I was found to be carrying it would lead to some unpleasantness (up to and including losing my job). I am very aware of concealment. It just seems... unhelpful, when I shop for guns/gear and am looking at small guns and holsters, and everyone wants to say "you're a big guy, you can conceal anything! Why would you want a mouse gun like that?"
Well, no, no I can't. Not reliably. If I were just going out on the town, or to someone's house, sure, because what's the worst that can happen if it's noticed? I get asked to leave? No big deal. When my livelihood is at stake, not so much.