Shortening rear end and backing brace?

Hey,
I am going to build a "B" or "C" body 8 3/4" rear end for my 71 dart. Is there a better choice to start with? I have been looking up Dana's but they are very expensive and this is a street car that may make the odd trip to the track.

Right now it has a complete 8 3/4" "A" body 4" SBP set up with drum brakes, that are in excellent condition. I don't want to cut this one up, when I am going to replace everything anyway.

The car is mini-tubbed and spring relocation done too. It's a 440 with a 4 speed.

My plan is to get the rear end sand blasted, ready for shortening and welding a backing brace on it.
My thought is to weld the old flanges to my very solid steel welding table, with the opening facing straight down and modify the backing support to fit then weld it in place. I plan on using a 2"x4" square tubing and triangleate it out to where I know the new flanges are going to be welded on.
I will be doing 2" stitch welds so I don't put to much heat in it, but should I be using Stick for this or MIG?

I figure this is the best way to keep the rear end straight with all the welding for the brace.

Does anyone have some sort of drawing or schematic of this brace? I can make my own but thought it may be easier to get some other idea's.

Then cut the rear end off the table and cut the tubes to the correct length to weld the new flanges back on. I have seen a couple different ways to do it, but I am going to use the long steel bar with spacers and sleeves to get it straight.

Any help, or support would be great, I really don't want to have to do this twice.
When I weld the new flanges on, they will also be stitch welded on and I am sure this will be done with stick also trying to minimize heat input?

I know I am forgetting something along the way yet!!!

Thanks,