Here are the pictures I promised,
first on Saturday I took to cutting the old sub frame apart around the upper a arm mounts.


then I cut the exact same section out of the donor frame I picked up on the far side of Kitchener.
I then proceeded to mock up and trim as required to get a nice fit with minimal gaps all around. (I cut the replacement piece a little long to allow for trimming to get the angles right)
I then tacked it in place, checked my measurements and proceeded to 3 and 4 pass weld it all around. its hard to see in the pictures but I've got about 1/2 inch of weld coverage on each joint with a gap no more than 1/8 " if not tight in most spots before welding, on the cross member on the underside I wasn't able to it very close because of miss cutting my new piece so what I did was cut a piece the exact same size as my gap, tapped it in with a hammer and 3 passed it all around.

I threw some flat black tremclad rust paint over everything just to cover it up until I'm ready for sandblasting and sealing up my engine bay.
and That was saturday.
Now today I was working on just the subframe torsion bar/ body mounts which were toast on the drivers side, the donor frame had been repaired so I fixed the initial repair on the donor frame and proceeded to cut out the old rotten steel to make room for my new torsion mount/ body mount.



I managed to get the new piece in there and welded the begesus out of it. I had to get a little creative on how I was going to make it strong because without removing the frame from the car I was only able to weld 3 out of 4 sides, what I did was I made the new piece fit just inside the top of the old stuff so I could weld it along the side up to an inch away from the main joint to spread out some of the load stress.
now I just have to weld on a rear brace I didn't get to today and the sub frame will be complete about 2 weeks ahead of schedule.
ps I was using a 110V gassless mig machine with .035 flux core wire, you don't need a big money machine to do quality work. and without 15 packs of cutting disks being on sale I would have been screwed. I think I have 4 left out of 15 after 2 days