3rd cylinder has been done. Pieces to attach cylinder to lower feeder tube and combine frame have to be made from scratch and welded in. Works very good and does not impact lift and lower speed either. If you have no luck in getting pieces PM me and I can get info for you.
You could also install the HD lift package from the 8120. You will have to see which way is more economical.
I'm not going to be any help solving your situation but I didn't want to see it just slide off the page.
Maybe you could give us some insight has to how you ended up in this situation with a NEW combine that won't lift the header? What were your reasons for not going with a bigger combine? Did the head and combine come from the same dealer?