Good input. What's your reasoning for welding the adapters in place?
I took about 1.5" out of the top and about .5" out of the front and rear of the outer fender. When you take an angle grinder to the fender, it separates the inner fender (that angles upwards to the top of the inner wheel well) from the outer fender. I got my outer fender how I wanted it and "pulled" the bedside about a half inch. I hammered the inner fender on the outboard edge where it angles up to the top of the inner wheel well (which was now detached) upwards a couple inches and tacked it back onto the bedside (or outer fender). Otherwise, my bedsides would flop around uncontrollably.
At the bottom, there wasn't enough material to work with so I made some small brackets to tack onto-
I hope that description wasn't too confusing. There is plenty of room to re-separate the inner from outer fenders and do further trimming. I have no doubt I can avoid any rub from 37s with 2" spacers. Will it look stock and not take any time or effort? No. But, I will not put fiberglass bedsides on my truck and my tires will not rub.