Whitedog,
I'm in kinda the same position. However, I think I figured out a way around it for the most part:
I'm going to leave the tub in my 52, cut a spare seat frame that I have down to take the back off of it, then use some channel steel to weld mounting points for the buckets. With the steel being shaped like this ], I figure I can take the end of it and make it look more like | on the ends so it will fit right on top of the old frame. At any rate, it's an idea that you can consider or throw out.
