yes exactly Y or -Y
Well I don't have the computing power to make 2**66 tries.
I have nothing to lose, I can only try
2**66 was just a quick estimation around which repeats start to show up, as you said you pick random 2**133 numbers.
You'd still need to make ~ 2**102
unique random selections (or simply, sequential BSGS steps) until you find the key.