Would the experts explain why their answer is correct? For both DD and 6 deck games playing heads up, standard rules, H17, no S.

when playing heads up.

1. Playing one hand only is best.

2. Always play 2 hands.

3. As much as possible, play 2 hands in positive counts, 1 in negative counts.

4. As much as possible, play 2 hands in negative counts, one in positive count.

I have utilized #3 but read from a better AP that #1 is best but no explanation. Your comments are appreciated.