Im 5'10" 230 pounds and wider than most at the shoulders .I Regularly fly with similar weight passengers, the gross weight would be "up there".
The 912 handles it extremely well,the 582 takes its time but is surprisingly good.
This is on a 3 and a 4.
The wide body mod will happen if I need to ever recover the fuse,but for now I have a bolster cushion that goes behind my back so our shoulders are not inline,this workers fine
A heavy passenger takes approx 5 kts off the cruise speed.