Wheel and Tire help

Do you think its possible to cut the bottom of the inside wheel well and just stretch it? And then weld a small piece in to close it off? 295/45/18 looks like the goal tire as they are cheaper than 285/50s

My current 275/50/15 are 11in section width and the 295/45/18 are 11.5 wide for nitto tires. At most I think I would have to move the springs in.

The tubs are only as wide as the springs with a 1/2" offset. And, stretching the bottom isn't going to cut it unless you sit WAY high in the back, especially with a 28" tire. The tubs taper up, so they get even smaller than they are at the springs. At their widest, the tubs are only 11.5" wide. Even with a fender roll, I seriously doubt you'll get enough clearance for a 295 without rubbing on the springs and quarters without a 3" relocation and a mini-tub.