Well, here is one of the only reviews I can find of the Null holster being worn. In those pictures, it is printing mildly even though the cover garment is a sweater. So I’m not seeing how that’s going to work with a collared shirt.
https://welikeshooting.com/reviews/g...holster-twist/
In any case, it illustrates what I’m talking about with various deep concealment shirt shoulder holsters I’ve used (none of which were Null holsters). It’s just hard to explain straps printing underneath a man’s shirt - and few professional shirts are heavy enough to hide even thin straps.
And the thing is, if I can wear an untucked sweater or polo, then I can conceal a full-size pistol in an IWB rig.