So I finally have the tank together, and it doesn't leak and the fuel level light works.
I have a 1998 R1100R, not a GS or RT, and what made the float work was the position of the sock. I have to admit the sock was in the correct position when I took it apart, and 45 degrees from most pics I have seen on the internet, such as this:

I presume with the difference in tank shape, the sock needs to be not pointed towards the closed float, but 45 degrees and pointed to the outside wall. (straight towards the plate)
Anyways it works, and I am hoping for Spring and being able to ride my bike. Next job is bleeding the breaks, but I do not expect any drama from that, considering I installed SS brake-lines last year.
I just thought I would close this thread and wish everyone an enjoyable riding season ahead.