I am 5'7", 164lbs and I can't do it. I can manage the 19 with a single port comp but not the X300... It's just too wide. My compromise was to use a TLR7 with the new Tenicor Sagax Lux which works great but is the maximum size I could comfortably wear and still retain a full range of motion when bending and squatting.
Thought I'd come back to this thread to eat some crow... Apparently I can carry a Roland Special with the correct gear and adjustments.
1.) Henry Holsters Spark with DCC clips
2.) Mastermind Tactics belt
3.) Wear my pants higher on my waist
The Spark is unbelievably comfortable considering how much gun it's concealing. I also tried the Bawidamann Gotham and it was a very close second but the footprint is wider than the Spark and didn't let me move the holster close enough to my centerline to prevent the light from digging into my inner leg. The Spark also conceals as good or better than anything else I've tried, as crazy as that seems. I don't even use a wedge but the extra length and width still pushes the grip into my body the best I've used... That extra footprint also eliminates any hotspots/pressure points on my pelvic region.
The MM belt removed the hoola hoop my previous very stiff tactical belt created. I miss the convenience of the Cobra buckle but the increased concealment is worth the extra hassle.
And finally, actually wearing my high waisted pants high on my waist gave me the extra space needed to fit the longer muzzle. It's an old man look for sure but with my shirt untucked no one can see it anyway. It felt weird for a few days but I quickly adjusted. I still can't believe I can fully conceal a Roland Special on my person And in relative comfort but I'm doing it so it's real. Deep bends can still be uncomfortable but normal sitting/driving is a non-issue. I've mowed grass on my zero turn in 100° heat for over 4 hours without even thinking about it and I spent a weekend installing a new shower in our bathroom, crawling, bending, squatting, etc, again without issue. Now my tiny seeming G19/TLR7 feels strange to wear, lol.