Definitely NOT 26k
I had offered adriana (26k) a rematch after my win against her with a 4-stone handicap (she was ranked 25k then). This time, we played evenly and I was slaughtered. Again, I made what mungo (4k) calls silly mistakes that are often from lack of mindfulness.
She agreed to give me 1-2 stones next time. One stone might still be a stretch since my best playing ability on a good day is barely 27k.
As I've mentioned a couple of times in KGS chats, rank is probably both a measure of skill and mental alertness. A shortage of either one can cripple a player's abilities.