It's encouraging that you were able to get things working. Kerberos has made me rethink my chosen career path on occasions where I was lost somewhere between what the proverbial brochure said was possible and what was happening in the environment I was configuring. Thanks for detailing your experience.
I do not work with IIS and SSRS as an admin but this was an interesting read and I picked up some general bits that I am sure will come in handy someday.
There are no special teachers of virtue, because virtue is taught by the whole community. --Plato