Stride will not help you in address mode, its a simple math, those prime numbers you found in address prefix are irrelevant as a pattern since multiple hashes from private key for generating address would kill any correlation. stride is used to make a collision between a sequential subgroup to a distributed targets based on a pattern, useful in BSGS or Xpoint, like when you use key negation and know the exact distance between targets, then you need to look for a very large prime number that is close to d/n (distance/sequential search(-n)).

for your second question, the Keyhunt behavior is not strange, that's the nature of compress mode, it checks both side of the elliptic curve for any given key.