Soil - my sativa SSH doesn't like too much food, I've discovered. It makes her leafy and ruins the buds. In fact, I fed her plain RO water for the last 3 weeks this last grow and she loved it. Easy on the nutes - this is a hazey plant. Just keep her alive and healthy, let nature do the rest. You can't pump-up the yield with this one so don't try. That is for indicas. You will find that you get a great yield anyway, just let the plant do the work, not chemicals.
As for pH, 5.9-6.3.
I'm sure that the indica phenotypes can take more feeding, from experience, but I would go easy anyway and work your way up, grow by grow, until you find the maximum level, if you are that way inclined...you will know when you've gone too far - this plant will tell you in a number of ways.