I just put new bushings in my BII. I had a couple to repair also. I had some old rubber ones still out in the shop, and while they are a little distorted, the majority of them seem to be around 1 1/4 in diameter. That's the part that sticks through of course, the OD of the complete bushing is much larger.
I see in the picture you have the same situation I did. It's difficult to to determine the center and where the hole needs to go. What I did is make a plate with the center hole punched out, and then when replacing the bushings I put it all together and got the body sat down, without welding the repair plate in. By doing that it found it's home where it needed to be, I marked it's location and also the outline where I could trim it off to look decent, and then I lifted the body back up, took that all apart, and then positioned and welded the repair piece, and then it was ready for final assembly after a little paint.