This is what I wanted to do last year but with a brand new son it was hard to find the time, and the funds. This year I'm taking my time and not worrying about getting it on the road asap.
Got the other side cut out and sanded down to bare metal. the arches are gonna be massive. I had a difficult time deciding how to replace the stiffness that was lost by cutting out the wheel wells.
I though about fitting a single peice of new steel to fill the gap but after thinking about how impossible it would be to find a perfect fit I decided to cut the steel into 1" wide strips and fill the gaps piece by piece. it took a long time but the new wheel wells started to take shape.
For eace piece I drilled a hole in the inner fender and used a cleco to hold it in place then fit and bent the next one, it was a pretty long process but it was pretty simple to do. You just have to make sure the fingers fit good. Thankfully My hanger has a huge sheet metal bender and a shelf full of celcos