Might be worth checking out similar threads in the forum, like this one
Not optimizing the ranking system and sticking to very simple buy/sell-rules bodes well for your returns!
You’re going to have to live with extremely high volatility with only 12 stocks, I’d increase to 15 or preferably 20. I’d also add a buy-rule like subseccount<some-limit to reduce the risk of overinvestment into a single sector.
Like I commented in the thread references above, the low turnover could be an issue, during testing it could be a good idea to force the model to have higher turnover, using nobars>200 as a sell rule for example. I also recommend to test the model using mod(stockid) (details in the thread referenced).