Change the way you dress.
Possibly change your holster.
I am not familiar with your holster, but I have no problem concealing a full-size M&P in a Desantis Intruder. I wear button-down shirts with a pattern (no solid colors) and a straight hang (like the Royal Robbins and Woolrich Tactical Series) and Polo shirts (solids and stripes) one size too big.
I can conceal certain pistols in belt holsters with these common modes of dress, too...
When you carry a gun you must modify your wardrobe - but the modification doesn't have to be extreme...the two keys are straight hang pattern and one-size-too-big...
Your size matters, too...I am 6'2" and weigh 230#...I can conceal guns smaller people can't...you gotta tinker to get where you want to be...
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The one thing you didn't mentioned, which is too often overlooked, is your belt.
What kind of belt are you using? Flimsy, squishy belts from Kmart or JCP will NOT serve you well.
The selection of a belt is just as important as the selection of a holster!.
I wear a Wilderness Explorer. If you require a dressier belt, check out Galco and numerous other holster makers. Whatever you choose must be rigid to keep even IWB holsters from shifting and moving away from you when you move. Belt selection is just as important for IWB as OWB.
The best concealment rig in the world won't live up to all it's hype unless secured with a good belt...