Does anyone ever actually use a tuckable that much? I've tried them and even with a small gun no matter where I place the holster on my hip or how loose I left the part of the shirt that wasn't tucked in there was a huge obvious bulge. I always thought that even to the untrained eye it would be obvious as a pounded thumb that you had something inside your belt.
I use one (DeSantis Sof-tuk, or however they spell it) once or twice a week, with a regular IWB the rest of the time. I usually have a cover garment, but when I go to church I have to take off my jacket and put on a choir robe, so I wear it there and on other unusual occasions when I can't manage a good cover garment. I don't tuck my shirt in tight, just a little loose blousing above the belt and it doesn't show. Don't look too hard, because no one else does.