Similar experience here. I started with a FS M&P .40 in a N82 pro holster.
Levi 541's are cut great for IWB carrying, they are looser around the waist while still "fitting" on the thighs, also Wrangler Comfort jeans have a stretch waist, perfect for IWB. Now having said that, I sold the .40 and went to smaller guns (I'm 6 foot , 210lbs 34" waist) now I rotate 3, a shield 9, a 9C and an XDM 3.8C .45. I have 2 holsters for each gun, all Stealthgear, a "Flex" OWB for each and a "mini" IWB for each.
In the winter I primarily use the Flex for all 3, it rides nice and high and tight against your side a loose sweat shirt completely conceals it.
In warmer weather I go IWB, the only one that's somewhat "tough " to carry IWb is the XDM .45 because it's heavier and I can feel it a lot more
but it still conceals OK. I know a couple of guys that carry the FS 9 and they really have to dress around it.
In Mass, the Libtards tend to freak out if they see a gun on you , so I try to be as "concealed" as Possible at all times.
with a FS piece it is a bit more difficult.