Trivia for you, in California at least, the load can extend back up to 4' before a flag is needed. That's old news of course, but from where do you measure? According to out DOT guy it is from the taillights of the hauling vehicle. On our rollback, our taillights are tucked under the bed about a foot. That leaves us only 3' of margin as measured from the bed before we need a flag. As I said, pretty much trivia.
I had a buddy with a one-ton with a 12' flatbed break down. He is a concrete contractor and had his truck loaded with stakes and tools. He was at about 12k lbs, but most of it was rearward. Our truck (since sold) was a Freightliner M2, so pretty hefty for a roll back. I pulled him up nose first. It felt pretty uncomfortable driving the truck loaded this way. The front felt really light. I only went about 5 miles and all was well. Wish I could have scaled the axles. Not sure I had much on the front.