FWIW on the handle attachment issue, I rebuilt my briefcase handle a while back and also built a travel case for my sxs, the latter being based on experience derived from the former.
The briefcase handle was attached with those pot metal mounts that, after a year or so of in and out of the car and office, just gave way. So, here's what I did.
I went to the Home Depot and bought a couple feet of 1/8 inch brass rod, a tap and die set sized to the rod, and brass nuts and washers sized to the threads from the die and rod.
I figured out how big a squared-off U of brass I would need to replace the existing pot metal, then cut sections of the rod to make a pair of them, threaded the rods ends and formed the unthreaded section of the rod into the two right anglesto make the hanger. I slid the rod through the handle proper, threaded a nut and washer onto each of the threaded ends all the way to the end of the threads nearest the handle, then slid the thing into the existing holes in the briefcase. On the inside ends, I checked for length, threaded on another washer and nut, tightened it down, hacksawed off the excess, peened the ends over and reset the lining. All accomplished, from design to completion, in an evening or two in front of the TV.
That was 10 years ago. No problems since. It'll probably outlast the next ice age.
Because of the peculiarities in the dimensions of the handle, etc., there was a bit of gymnastics involved in tapping the threads onto the rod and then bending. But, I had excess material to practice on - the final job required maybe 8 inches of rod.
I did something similar but bigger for the travel case.
