I carry mine with a TLR-2G and RMR on it with a guardian concealment holster. It's a belt tester. I have worn it that way for 14 hours at a time. I have it set at almost the maximum depth you can set up with maximum cant, with only the grip and RMR above the belt line. At the 3:15 - 3:30 area. Just a loose fitting t-shirt (tradesmen fit from Duluth Trading Company), and it will show if I bend a certain way. Yes, it does show that something is on my belt, but I keep a flashlight visible on the other side.
After a few days of working, I asked the guys at work if they noticed. No one did. But I say you will need pants a size bigger if you don't already.
I find it interesting that in the video he said he could move the holster back (towards 4 or 4:30) and get better concealment. My experience is 3 o'clock hides the butt the best whether its a P238, Glock 27, or 1911. What am I missing or doing wrong? I'm 6'1 and 215, a little soft around the middle which I argue helps with concealment. My skinny friends have a harder time concealing I think. Is this normal? I have carried my FsN in IWB hybrid which I think is close to the same size as the FNX, and its not exactly concealed under just a t shirt or loose button down.