I have rules setup, but it's not quite 100% mechanical. I'd say maybe 90% of it can be automated. The other 10% is subjective based on how price action looks like.
30% dd is high. I also used to allow high numbers but in practice this was nauseating especially when the real DD was approaching 40% for various reasons. Sitting in a 30% dd for a longer period of time is mentally devastating and not worth it. Something like 15% is far more tolerable.