Need to Repair Lead Closet Flange but the Pipe is Crooked!

]My lead over brass closet flange needs repair. There is only about 5/16" of lead remaining in the front of the flange:

I was going to cut off the lead part and join the copper pipe to ABS with a flexible coupling. I then noticed that the pipe is very crooked. It is about 5 or 6 degrees off plumb. How much leeway does a flexible coupling allow? If the ABS is aligned with the copper, one side of the flange will be lifted by 3/4" . The pipes might not even align if the lead section is hiding even more crookedness. Even worse, I think the pipe might be smaller that typical 3" pipe. I calculated 3.14" which is too small for the coupling I bought. (Pro-Connect 56-33)

I found a lead repair part that might work:
http://www.renodepot.com/en/sleeve-lead-toilet-sleeve-04825002

Does anyone have any tips on how to use this part. I figure that pounding this sleeve cold into the old one would be insufficient.

So I talked to the people at the store about the lead sleeve. One sales clerk said that you just have to jam it into the old one and the deforming lead will make a gas tight seal. Another clerk said that you need to solder the two together. Would tin/lead solder work? I would think that the solder would be harder than the lead and might cause tearing when I try to peen it down.